GIA Knowledge Sessions
The GIA Knowledge Sessions are a series of talks and seminars that engage participants in the most diverse and pressing issues in gemology today, including gemstone origin, laboratory-grown stones and new discoveries in field gemology. These webinars are brought to you by GIA Ph.D.s, field gemologists, educators and research scientists whose experience and expertise offer a trove of gem knowledge.
The sessions are free and open to the public. Registration in advance is required to attend.
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Past Sessions
Webinars in English
December 16, 2021 | Quantifying Diamond Fluorescence and Its Visual Impact
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The impact that fluorescence has on a diamond’s appearance has long been a hot topic of debate. A team of GIA scientists recently embarked on a study to quantify the relationship between the intensity of a diamond’s blue fluorescence and its effect on face-up and table-down color, brightness, and transparency. Follow GIA Director of Metrology and Quality Control Dr. Yun Luo as she uncovers the GIA team’s latest discoveries.
November 18, 2021 | A Glimmer of Hope: A Look at the World’s Most Famous Blue Diamond
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The Hope diamond is perhaps the most famous jewel in the world. In addition to its illustrious royal provenance, it is a rare marvel of nature due to its size, blue color and red phosphorescence. Follow Senior Manager of Diamond Identification Dr. Sally Magaña as she delves through both the history and recent scientific discoveries surrounding this gem.
October 21, 2021 | Understanding the Origin of Natural Diamonds
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Do you know your diamond’s origin? Join GIA Research Scientist Dr. Evan Smith and GIA Global Business Development Director Matt Tratner as they explain why diamond origin is important in today's marketplace, some of the challenges that exist in identifying a diamond's country of origin, and how GIA uses the scientific matching process to confirm a diamond's origin.
September 30, 2021 | Unusual Phenomenal Colored Stones
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From star sapphires to opals to alexandrites, phenomenal gems are nothing short of, well, phenomenal! They each have special properties that allow them to interact with light in an unusual way, causing them to display effects such as asterism, play-of-color and color change. Journey along with GIA researchers Aaron Palke and Ziyin Sun as they dive into the science and mystery of phenomenal gems, nature’s rock stars.
September 16, 2021 | Playing the Blues: An Overview of Sapphire Treatment
10:00 a.m. PDT
Speakers: Wim Vertriest
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September 2, 2021 | Through the Years: Interesting Discoveries from the GIA Laboratory
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From color-changing diamonds to gemstones with unusual growth features, the GIA laboratory has received many intriguing submissions over the years. These gemstones have offered insight into the treatments, geology and popularity of gems as well as revealing many surprises. Join Dr. Sally Magaña, Senior Manager of Diamond Identification, and Nicole Ahline, Senior Staff Gemologist, as they offer a look at some of the rarest, most unusual and captivating specimens submitted to the laboratory.
August 19, 2021 | Minerals Discovered and Named at GIA
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Did you know that—although scientists have classified thousands of minerals—new ones are still being discovered every year? Some of these minerals were even discovered and described by GIA! How do new minerals get discovered and how do they get named? Hear firsthand from GIA Senior Manager of Research Dr. Aaron Palke and GIA Research Scientist Dr. Evan Smith on how they discovered johnkoivulaite and crowningshieldite, two fascinating additions to the world’s growing list of minerals.
August 5, 2021 | Highlights from Gems & Gemology: Spring 2021 Issue
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Curious about what’s inside the latest edition of G&G? From a glimpse into the internal structure of natural pearls to uncovering spinel micro-features, this webinar by Senior Manager of Pearl Identification Dr. Chunhui Zhou and Manager of Colored Stone Identification Nathan Renfro is not to be missed. Tune in as they dive into the latest and greatest content of GIA’s prestigious research publication.
July 22, 2021 | A Gemstone’s Journey through the GIA Laboratory
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Ever wonder what happens to your colored stone as it moves through the GIA laboratory? From submission to photoshoots to advanced testing, each gemstone undergoes several processes before receiving an GIA identification report. Journey with Senior Staff Gemologist Nicole Ahline as she takes us on a behind-the-scenes look at a gemstone’s journey through our laboratories.
July 8, 2021 | Gemstones from the Sea
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Marine treasures such as shells, pearls, and corals have been valued by humankind since antiquity. These biogenic gems are produced by marine organisms and possess mineral compositions similar to one another. What is the earliest evidence of human use of these materials? What mollusk species commonly produce pearls? What is precious coral and what are its major sources? What other biogenic gem materials can be found in our oceans? Dive deep into the source and science of these gemstones with GIA Senior Manager of Pearl Identification Dr. Chunhui Zhou.
June 24, 2021 | Understanding Jadeite
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Jadeite Jade is the most valuable translucent to opaque gem. How do jadeitites form in nature, and where are their most important sources? What’s the difference between ‘Jadeite Jade’ and ‘Fei Cui’, and what do the terms “A Jade”, “B Jade” and “C Jade” mean in the trade? Tune in as Dr. George Harlow from American Museum of Natural History and Xiaodan (Holly) Jia from GIA Hong Kong cover the formation, sources, identification and treatments of this precious gem from an international perspective.
June 10, 2021 | Sapphires: From Ceylon to Ethiopia
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Since antiquity, sapphires have symbolized truth, fidelity and the heavens. Not only are they sought-after globally, they are also produced at numerous locales across the globe. The most famed historical sources are of course Kashmir and Ceylon/Sri Lanka, but numerous other deposits, both ancient and modern, have shaped the sapphire trade now. Journey along with Manager of Field Gemology Wim Vertriest as he takes us from the illustrious digs in Yogo, Montana to the massive operations in Australia to the recently discovered sapphire fields of Madagascar in pursuit of these true blue classics.
May 27, 2021 | Identifying Mineral Inclusions in Diamonds
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Did you know that diamonds are the perfect time capsules, trapping minerals inside them as they form and bringing these minerals with them to Earth’s surface? The minerals trapped inside diamonds are called inclusions and can affect the clarity of a diamond. To scientists, however, they are treasures, telling much about a diamond’s formation as well as Earth’s geologic history and processes. What secrets does your diamond hold? Join GIA Research Scientist Dr. Evan Smith as he dives into diamond inclusions and explores the methods used to identify them.
May 13, 2021 | The Latest Discoveries from Gems & Gemology
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Curious about recent hot topics from the gem world, such as low-temperature heat treatment of pink sapphires from Madagascar, rose-cut stones in artifacts from the seventeenth century, or how to distinguish blue amber from different geographic origins? Dive into the latest issue of Gems & Gemology, GIA’s prestigious scientific journal, with contributors Dr. Sally Magaña and Nicole Ahline.
April 29, 2021 | Colorless Diamonds
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Colorless natural diamonds or “white” diamonds are admired all over the world for their brilliance and fire and treasured as symbols of romance. But did you know that most colorless diamonds aren’t actually colorless? Many contain subtle hints of yellow, brown or gray. In this webinar, we’ll discuss the causes of color for diamonds on the D-to-Z scale, trends seen in their quality characteristics, and how these diamonds are distinguished. Prepare for a brilliant journey with Dr. Sally Magaña, Senior Manager of Diamond Identification, as she dives into the science of one of the world’s most popular gems.
April 15, 2021 | X-Rays and Their Use in Gemology
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Did you know that X-rays not only reveal bones but have applications in gemology as well? X-rays are used to separate natural pearls from cultured ones and to assist in the origin determination of some gems. This technique is unique in that it can be used on opaque as well as transparent gems and is crucial to some aspects of gem identification. Find out more about X-rays with Nick Sturman, Consultant to GIA, in this latest GIA Knowledge Session.
April 1, 2021 | Geology 102 for Gemologists: The Natural Processes that Form Colored Gemstones
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Gemstones require extraordinary geologic circumstances to form. Not only do different minerals need to meet under the right conditions and crystallize, but certain rare elements also need to be part of the mixture for the crystal to be the right color. Tune in as Wim Vertriest, supervisor of field gemology, builds on the earth science introduced in “Geology 101 for Gemologists” to explore how alexandrite and spinel form in the earth’s crust and why pegmatites – an igneous rock that is the source of an incredible variety of gems and mineral specimens – is known as ‘natures treasure chest.’
March 25, 2021 | A Look at Kimberlites: The Volcanoes that Carry Diamonds
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Natural diamonds crystallize at great depths, far deeper than we can dig or drill into the Earth. So how is it that diamonds can be found among us? The answer lies in rare and unusual volcanoes called kimberlites. These deeply-seated volcanic eruptions can sometimes pick up diamonds, along with other minerals and rock fragments, and blast them to the top. Think of kimberlites as elevators that diamonds use to ride up to Earth’s surface! Tune in as GIA Research Scientist Dr. Evan Smith digs deeper into these super-charged volcanoes and uncovers the role they play, not just in transporting gem diamonds, but in revealing the geological workings of the Earth.
March 18, 2021 | Green Gemstones: History, Lore and Gemology
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Throughout history, green gemstones have been associated with fertility, serenity and even luck and jealousy. What is the history behind these associations? In celebration of spring and St. Patrick’s Day, spring into the lore, history and science of green gemstones with Research Librarian Judy Colbert and Senior Manager of Research Dr. Aaron Palke. Learn about the scientific properties and symbolism of some of the most popular, rare and unique green gemstones in the world!
March 11, 2021 | Microfeatures of Gems: Geologic Implications
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Inclusions are more than imperfections or clarity characteristics. They can teach us much about gemstones’ journeys and reveal otherwise inaccessible information about Earth’s formation. What stories do diamond inclusions tell about Earth’s mantle? What do rutile needles and three-phase inclusions teach us about corundum and emerald, respectively? Follow Manager of Gem Identification Nathan Renfro and Senior Manager of Research Dr. Aaron Palke as they offer an up-close look into the microworld of gems and show us how this world reveals secrets about Earth’s geologic processes at large.
March 4, 2021 | Color-Change Diamonds
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Did you know that certain diamonds can temporarily change color when exposed to heat, ultraviolet light, or even when kept in the dark? Some natural greenish diamonds are known as “chameleon” diamonds due to this property. Other natural pink diamonds and some color-treated and laboratory-grown diamonds can also change color in unexpected ways. Before this phenomenon was known, there were stories of customers returning diamonds they purchased because the diamonds turned out to be the “wrong” color! What exactly causes these interesting diamonds to shift their hues? Find out as GIA senior manager of diamond research Dr. Ulrika D'Haenens-Johansson and senior research scientist Dr. Mike Breeding dive into the mystery of these ultra-cool gems.
February 25, 2021 | Fall 2020 G&G: D-to-Z Diamonds, Royal Jewel Auctions, Vietnam Field Report and More
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G&G’s most recent issue captured the past, present and future of the gem industry – with an overview of European royal jewelry sales (including the sale of Marie Antoinette’s jewelry), in-depth coverage of D-Z diamond knowledge (such as causes of color and formation) and a journey into Vietnamese pearl farming. Tune in as G&G contributors Troy Ardon and Nicole Ahline touch upon these and other highlights from the most recent publication of GIA’s prestigious scientific journal.
February 18, 2021 | Tangled up in Neon Blue: A Review of Paraíba Tourmaline
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Paraíba tourmaline, discovered in Brazil the 1980s, took the gem world by storm. Neon blue to greenish-blue and colored by copper, they were gems unlike any other. It was a pleasant surprise, therefore, when other glowing, copper-colored tourmalines were discovered in Mozambique and Nigeria in the 2000s. Since then, all tourmalines with these characteristics have been known as Paraíba tourmaline. What is the history behind these finds and the science behind their beauty? Follow Senior Staff Gemologist Dr. Yusuke Katsurada as he dives into the unique properties of Paraíba tourmaline as well as how GIA scientists determine the geographical origins of these scintillating stones.
February 11, 2021 | Red Gemstones: History, Lore and Gemology
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Throughout history, certain red gemstones such as ruby, garnet and spinel have been associated with love and romance. What are the science and history behind these associations? In honor of Valentine’s Day and lovers everywhere, GIA Senior Manager of Research Dr. Aaron Palke and jewelry designer and author Joanna Joy Seetoo are diving into the properties that have caused certain red gemstones to capture the popular imagination and become ultimate symbols of romance. Whether you’re a lover or just love gemstones, make sure to tune in!
February 4, 2021 | Gems of the Southwest
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The American Southwest has long been known for its distinctive jewelry, with the most iconic perhaps being Native American turquoise jewelry. An integral part of Navajo culture, turquoise beads are given to babies at birth and used in initiation rites and marriage and healing ceremonies. Other gemstones like opal, mother-of-pearl, and onyx have also been cherished throughout this region’s history. How have gemstones shaped the lore and culture of this region? What are the geologic conditions that allowed for the formation of these gemstones? And what sets these gemstones apart from those found in other places in the world? Discover all this and more as GIA scientist Aaron Palke and Emerald Tanner take us on a gemological journey into the rugged American Southwest.
January 28, 2021 | The History of Engagement Rings
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Rings have been used as symbols of love throughout history, so it is no wonder that they became part of the tradition of proposing marriage. When did the history of engagement rings start, why are engagement rings placed on the “ring” finger, and how have their styles evolved through the centuries? Tune in as Kate Waterman, GIA Instructor of Gemology, takes us on a journey through the history of one of the most meaningful and popular types of jewelry in the world.
January 21, 2021 | Natural Rough Diamonds: Crystal Shapes and Surface Features
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Once cut and polished, diamonds of similar size, shape and quality may look similar to the unaided eye. But in their rough form, natural diamonds have distinctive morphologies that tell much about their formation and their volcanic journey to Earth’s surface. Natural diamonds can form as glassy octahedral crystals, flat macles, in unusual spherical shapes and more. During their volcanic transit up to Earth’s surface, they also often acquire intricate markings from corrosive fluids. Tune in as GIA Research Scientist Dr. Evan Smith unravels the story behind rough diamonds’ unique morphologies.
January 14, 2021 | Emerald Sources: The Grass is Always Greener on the Other Side
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Emerald has been coveted throughout human history. Only a handful of deposits were known during antiquity, but today, emeralds are mined all over the globe. Embark on a journey with Supervisor of Field Gemology Wim Vertriest as he explores the history and evolution of the world’s most important sources of emerald – from Cleopatra’s ancient Egyptian mines to the fabled mines in Colombia to more recent deposits in Ethiopia. This webinar will take you from the mountains of Afghanistan to the savannahs of Zambia, from the frozen Arctic to tropical jungles, detailing how and where people have found one of the most valuable treasures in the world.
January 7, 2021 | Natural Yellow & Orange Diamonds
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Yellow and orange diamonds both owe their color primarily to tiny amounts of nitrogen in their structure. Yet, while yellow diamonds are the most common fancy color diamonds, orange diamonds are among the rarest. What causes the difference in color and rarity between yellow and orange diamonds? Join Senior Research Scientist Dr. Mike Breeding as he investigates the atomic-scale characteristics that produce the colors of these dazzling gems.
December 17, 2020 | Short Takes: Recent Highlights from G&G’s Regular Columns
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GIA’s quarterly academic journal, Gems & Gemology, has relayed a wealth of gemological knowledge to industry professionals since 1934. In addition to articles on groundbreaking research, each issue contains short but insightful entries in the Lab Notes, Micro-World and Gem News International sections, covering notable gem submissions to the lab, gem inclusion scenes and pressing gem topics from around the world. Explore recent publications on diamonds and colored stones in these three unique columns with GIA research scientists Dr. Sally Magaña and Nathan Renfro and managing editor of Gems & Gemology, Stuart Overlin.
December 10, 2020 | Where Do Yellow Type Ib Diamonds Form in Nature?
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Yellow diamonds with isolated nitrogen are rare and dazzling, accounting for less than 0.1% of natural diamonds. This is because, over time under high temperatures, the isolated nitrogen atoms that cause many of these diamonds’ intense yellow colors will aggregate and turn the diamonds pale yellow or near colorless. What allows these rare yellow diamonds to retain their color? Tune in as GIA Research Scientist Dr. Karen V. Smit explores the atomic makeup and geologic journey of these stunning treasures.
December 3, 2020 | Melee Diamond Analysis
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Melee diamonds are the most prevalent stones in the market, and an integral part of the jewelry industry. They represent a new identification challenge owing to their very small size. With the emergence of laboratory-grown diamonds in larger quantities, the ability to efficiently and accurately separate melee-sized natural stones from laboratory-grown diamonds has become critical. Join GIA Senior Research Scientist Dr. Mike Breeding as he explores the world of melee diamond analysis and the unique challenges of these small stones.
November 19, 2020 | Behind the Scenes Part II: Untold Stories from GIA Field Gemology Expeditions
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Field gemologists are the modern-day explorers in the gem world, journeying far and wide to document mining culture and gem geology. Not only is their work instrumental to gem origin research, but it also offers us fascinating insight into the communities that bring us these dazzling treasures. Join Senior Manager of Research Dr. Aaron Palke, Supervisor of Field Gemology Wim Vertriest, and Director of the RTL Gemological Library Robert Weldon as they take us on another thrilling field gemology journey, narrating stories through highlights from their previously unpublished photograph collection.
November 12, 2020 | The Sustainability Minefield: What Does Sustainability Mean in Jewelry and Why Should We Care?
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Ethical jewelry will be as important in the future as digital technology is today, but it is currently a confusing and complex area. Author and journalist Melanie Grant expands on topics discussed in her book, "Coveted: Art and Innovation in High Jewelry," with a panel of experts as part of GIA’s Knowledge Sessions series. She will be joined by Susan Jacques, President and CEO of GIA, Dr. Raquel Alonso-Perez, Curatrix of the Mineralogical and Geological Museum at Harvard University, Livia Firth MBE, Founder and Creative Director, Eco-Age, and high jewelry artist Alexandra Mor for what will be a spirited discussion.
November 5, 2020 | Laboratory-Grown Colored Gemstones: Crystal Growth Methods
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Advancements in technology have allowed us to create laboratory-grown gems in greater variety and higher quality than ever before. How are laboratory-grown gemstones such as ruby, sapphire, spinel, alexandrite and emerald produced? And how do the various growth methods affect their quality and appearance? Join Education Operations Technical Advisor Dr. Jennifer Stone-Sundberg as she covers laboratory-grown gem history, crystal growth methods for both jewelry and industry use, the market for laboratory-grown gems, as well as ways to identify these man-made gems.
October 29, 2020 | Superstitions Surrounding Gems and Jewelry
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Gems and jewelry are more than just beautiful. For millennia, they’ve been fraught with symbolism — thought to contain medicinal powers and be able to ward off evil or bring their wearer joy and good fortune. Some jewels, on the other hand, are the opposite and are rumored to be cursed! Follow Senior Research Librarian Rose Tozer as she explores the beliefs and superstitions people have held about gems and jewelry throughout history. Learn about “cursed” gems, mourning jewelry, charms, amulets, jewelry symbols, such as the evil eye, and animal motifs, such as bats, scarabs, snakes, skulls, spiders and more!
October 22, 2020 | Natural Blue Diamonds
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Natural blue diamonds are among the most valuable and famous of fancy color diamonds. From the Hope diamond with its fiery phosphorescence to hydrogen-rich diamonds with their intriguing Alexandrite effect, blue diamonds have always captured our imagination. Tune in as Dr. Sally Magaña – Sr. Manager of Diamond Identification – explores the science of blue diamonds and their close cousins, violet and gray diamonds, and delves into the stories of these legendary stones.
October 15, 2020 | Furnaces, Fluxes and Filling: A Review of Ruby Treatment
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Many gems are treated to improve their appearance. While treatments can be controversial, they help provide a market for a wide variety of qualities of natural gemstones, which helps keep the supply chain going. Ruby, the king of gemstones, is no exception in often being treated. The degree of treatment varies from none to minimal to a total make-over and can affect value accordingly. Follow GIA Supervisor of Field Gemology Wim Vertriest, as he explores common ruby treatments, their results and how to identify them.
October 8, 2020 | The Sapphires of Montana
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When the first prospectors set out for the American west, they were looking for gold, and in Montana they found their share. But some of these unwittingly lucky miners also found another dense precious mineral — sapphires. Most of the sapphires found in the 1800s in Montana were for industrial use. But in the late 1900s, heat treatment processes were developed that made Montana sapphires one of the most important American-mined gems. Join GIA researchers Nathan Renfro and Aaron Palke as they unearth the history and gemology of these stunning jewels.
October 1, 2020 | The Evolution of Laboratory-Grown Diamond Evaluation at GIA
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Both the quality and quantity of laboratory-grown diamonds have increased in the past several years. GIA’s reports for laboratory-grown diamonds have evolved as consumers’ knowledge and interest have grown. What has changed in the 14 years since GIA first started issuing reports for laboratory-grown diamonds? Discover the evolution of these man-made gems and learn about GIA’s new reports for laboratory-grown diamonds with Senior Research Scientist Mike Breeding.
September 24, 2020 | The History of Diamond Cutting and Polishing Technology
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Diamond is one of the hardest natural materials on earth, and cutting and polishing it is no simple feat. In recent decades, technological advancements such as laser cutting have greatly enhanced the ease and precision of diamond cutting, but artisans have been polishing diamonds since at least the end of the Middle Ages! How is it even possible to cut and polish this exceptionally hard material? How does human skill unleash a diamond’s brilliance? Learn the answers to these questions and more from GIA Research Scientist Dr. Evan Smith as he covers the history of diamond polishing and shares his own experience cutting diamonds for scientific research.
September 17, 2020 | Natural Pink Diamonds
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Natural pink to red diamonds are among the rarest and most desired fancy colored diamonds. How they form is still a mystery — but scientists have observed that the vast majority of pink diamonds have a 550 nm absorption band, which indicates that shear stress and deformation of the crystal structure had occurred while the diamond was deep within the earth. Tune in as Dr. Sally Magaña — Sr. Manager of Diamond Identification — dives into the science of pink and red diamonds and unravels the mysteries of these enchanting stones.
September 10, 2020 | A Comparison of Diamonds and Colored Stones: Geographic Origin to Geology and More
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Diamonds and colored stones are often considered to exist in entirely different realms in the gem and jewelry industry. This might partly be due to the fact that they are mined and brought to market so differently. Diamonds are primarily mined in large, industrial-scale operations, while colored stones such as rubies, sapphires and emeralds are typically produced by smaller-scale, often artisanal, operations. Their quality is also assessed very differently. Nonetheless, both diamonds and colored stones have helped scientists unlock secrets about Earth’s geology. Tune in as GIA Research Scientist Dr. Karen Smit and GIA Senior Manager of Research Dr. Aaron Palke reveal why these gems have more in common than you may have imagined.
September 3, 2020 | Natural Green Diamonds
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Naturally colored green diamonds are among the rarest of all colored diamonds. Unlike other diamonds that get their color deep in the earth, most green diamonds come into contact with radioactive fluids near the earth’s surface that create structural defects and produce their green color. Diamonds can also be turned green by irradiation treatment. Can natural green diamonds be separated from their treated counterparts? Unravel their mysteries with Senior Research Scientist Dr. Mike Breeding.
Aug 27, 2020 | Diving into the GIA 7 Pearl Value Factors™
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While diamonds have four primary areas of assessment (the 4Cs), pearls have seven! These include color, luster, nacre, surface and more. Evaluating pearl’s enchanting beauty can be quite complex. Did you know that in addition to bodycolor, some pearls also have overtone and orient? That’s why GIA has developed a systematic technique for evaluating pearls. Follow Senior Staff Gemologist (Pearls) Akira Hyatt as she explores the GIA 7 Pearl Value Factors™ and its recent updates, as well as introduces the new Cultured Pearl Classification Report.
Aug 20, 2020 | Glowing Diamonds: Fluorescence and Cathodoluminescence Imaging of Growth Structures and Defects
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Did you know that roughly 35% of diamonds fluoresce or glow under longwave UV light? Besides longwave UV radiation, other methods can be used to “excite” diamonds so that even diamonds classified as non-fluorescent will glow. These methods are important to scientists, because a diamond’s glow can reveal unique and colorful growth patterns that help scientists separate natural diamonds from those that are laboratory-grown. Join us as Sr. Manager of Diamond Research, Dr. Ulrika D’Haenens-Johansson, shines a spotlight on the importance of fluorescence and cathodoluminescence in diamond identification and research.
Aug 6, 2020 | The Microworld of Gemstones
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The microscope is one of the most powerful instruments for analyzing gems. The inclusions contained within a gem as well as the features found on the surface can reveal a story about that gem. Get an up-close look at the microworld of gems with GIA Manager of Identification (Colored Stones), Nathan Renfro, and learn both standard and advanced microscopic techniques as well as the principals of lighting and photomicrography. This microscopic exploration is the beginning to uncovering the secrets hidden within the gemological microcosm.
July 30, 2020 | Diamond Ages: Are Diamonds Forever?
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Older than the dinosaurs and almost as old as Earth itself, diamonds are windows into the mysteries of our planet’s continuing geologic evolution. How old are the oldest diamonds and are diamonds still forming now? How are diamonds dated and why doesn’t carbon dating work on them? Join GIA Research Scientist Dr. Karen Smit and Senior Staff Scientist Dr. Steven Shirey of the Carnegie Institution for Science’s Earth and Planets Lab as they explore diamond dating and what diamonds teach us about the Earth.
July 23, 2020 | The Art of Photographing Minerals, Gemstones and Jewelry
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Robert Weldon, director of GIA’s library, has photographed some of the most extraordinary jewelry and gem specimens in the world. His work has graced the pages of “Splendour and Science of Pearls” and GIA’s scholarly journal, Gems & Gemology, to name just a few. Gems are known for the spectacular way they interact with light — glowing with color, sparkling or displaying fascinating phenomena. How do you capture their essence with a single shot? Peer through Robert Weldon’s camera lens as he talks tools, lighting, props and everything gemology.
July 16, 2020 | The Science Behind Fancy Color Diamonds
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Colored diamonds are priceless marvels of nature. From red and pink to green, blue, purple and brown, they exist in a rainbow of colors, caused by factors such as geologic forces, exposure to radioactive fluids or minerals, or atoms from trace elements being trapped in a diamond’s crystal lattice. Dazzled by these mysterious treasures? Tune in as Dr. Sally Eaton-Magaña — Sr. Manager of Diamond Identification — explores the science of diamond color and how fancy color diamonds are created within the earth.
July 9, 2020 | GIA Research — Not Just for Scientists
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Ever wonder who plans GIA courses and what goes into them? Gemology is part science, part art, part business. That’s why our education is fueled by GIA research — including our unique field gemology explorations — as well as informed by the information and experience of people throughout the industry. Whether you are a GIA alum or are simply curious about GIA education, tune in to “GIA Research — Not Just for Scientists” presented by Dr. Tao Hsu — Director of Global Professional Development — to get a behind-the-scenes look at how we design our world-respected curriculum.
July 2, 2020 | Geology 101 for Gemologists: The Natural Processes that Form Colored Gemstones
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What makes a gemstone rare and why are some gems rarer than others? The answer lies in gemstone geology. Some gems, such as emerald, require extraordinary geologic circumstances to form. Not only do different rock types need to meet under the right conditions and crystallize, certain rare elements often also need to be part of the mixture for the crystal to be the right color. Wim Vertriest, supervisor of field gemology, covers the chemistry of Earth’s crust and the geologic criteria for forming rubies, sapphires and some of the world’s most valuable gems.
June 25, 2020 | Diamond Color Treatment and Its Identification
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Natural fancy color diamonds acquire their color in a variety of ways, such as through trace elements, radiation and crystal lattice distortion. What about laboratory-grown fancy color diamonds? Or natural diamonds that have undergone treatment to change or improve their color? How are they created or treated and how do GIA scientists detect them? Tune in as Dr. Wuyi Wang, vice president of research and development, offers insight into diamond coloration, treatment techniques and the identification challenges facing gemologists today.
June 18, 2020 | Tools of the Trade: The Advanced Analytical Equipment Used in GIA Laboratories
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From loupes and microscopes to more advanced instrumentation, researchers use a host of tools to help them identify and analyze gems. Curious about how spectrometry helps scientists measure chemical impurities? Want to learn about laser ablation inductively coupled plasma mass spectrometry? Follow senior manager of research, Dr. Aaron Palke, on a behind-the-scenes tour of the tools used in a modern gemological laboratory, seeing with new eyes how scientists employ advanced analytical equipment to identify and characterize the gemstones that pass through GIA.
June 11, 2020 | Diamond Exploration & Mining
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Each year, mining companies invest hundreds of millions of dollars globally in finding new diamond deposits. Few of these explorations actually succeed. How do geologists decide where to look, what tools do they use to home in on diamonds and how do they know if they’ve discovered a commercially viable diamond mine? And once mining begins, what does diamond mining look like? GIA Research Scientist Dr. Evan Smith digs deeper into the process of unearthing these scintillating gems.
June 4, 2020 | An Overview on Pearl Identification: Techniques and Challenges
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The nacreous and non-nacreous layers that make up a pearl conceal many mysteries but also offer many clues to the gem’s origin — for those who can read them, that is. How do we know if a pearl is natural or cultured, saltwater or freshwater and what mollusk created it? Furthermore, how do we detect treatments especially on pearls' colors? GIA Manager of Pearl Identification Dr. Chunhui Zhou dives into pearl identification methods. From simple observation to x-ray radiography and DNA barcoding, learn how and why GIA scientists analyze these unique and lustrous treasures.
May 28, 2020 | Behind the Scenes: Untold Stories from GIA Field Gemology Expeditions
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GIA field gemologists journey far and wide to document gem geology and mining techniques. Behind their endeavors are moving stories, humorous anecdotes and fascinating local lore. Senior Manager of Research Dr. Aaron Palke, Supervisor of Field Gemology Wim Vertriest, and Director of the RTL Gemological Library Robert Weldon offer an exclusive look at GIA field gemology expeditions through previously unpublished photographs.
May 21, 2020 | An Exclusive View of the Jade Auction
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Jadeite is the only colored gemstone whose auction price can rival that of ruby, emerald and sapphire. What is jadeite’s enduring appeal and what factors determine this gem’s value? Journey with Dr. Tao Hsu, geologist and director of global professional development for GIA education, as she explores a jadeite auction at the exclusive Myanma Gems Emporium in Myanmar — the country that produces over 90% of the world’s jadeite. Pick up insider tips and knowledge along the way!
May 14, 2020 | Laboratory-Grown Diamonds from China
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China is the world’s largest producer of laboratory-grown diamonds for industrial use and is now a significant producer of gem-quality laboratory-grown diamonds. What impact do Chinese laboratory-grown diamonds have on diamond prices and the jewelry industry? Find out as Dr. Wuyi Wang, GIA vice president of research and development, breaks down how and why laboratory-grown diamonds are produced in the world’s second-largest economy.
May 7, 2020 | Rubies: Connecting Sources, Treatment and Science
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Known as “the king of precious stones,” untreated rubies are some of the most valuable colored gems in the world. Find out why as Wim Vertriest, supervisor of field gemology at GIA Bangkok, explores the mining, treatment, lore and politics of these legendary gems.
April 30, 2020 | Fascinating World of Pearls and Shells
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We’re shelling out pearl knowledge with a webinar by Nick Sturman, senior manager of global pearl services at GIA. Do all bivalves, including oysters, clams and mussels, produce pearls? Which pearl types are the most popular and where are they found? Travel with us as we dive into the world of these rare organic treasures.
April 23, 2020 | GIA’s Field Gemology Program: A Research Based Approach to Origin Determination
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Senior manager of research, Aaron Palke, Ph.D., expounds on advanced research techniques to determine gemstone origin and how traceability may be the next challenge GIA undertakes.
April 16, 2020 | Laboratory-Grown Diamonds: Updates and Identification
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GIA senior research scientist, Dr. Mike Breeding, wants to tell you the story of laboratory-grown diamonds. If all diamonds are made of carbon, what separates laboratory-grown from natural?
April 9, 2020 | The Unique Story of Natural Diamond
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Research scientist, Dr. Evan Smith, explores the origin of natural diamonds and discusses their significance from the perspective of Earth science.
Webinars in Mandarin
November 18, 2021 | X-Rays and Their Use in Gemology
Did you know that X-rays not only reveal bones but have applications in gemology as well? X-rays are used to separate natural pearls from cultured ones and to assist in the origin determination of some gems. This technique is unique in that it can be used on opaque as well as transparent gems and is crucial to some aspects of gem identification. Find out more about X-rays with Dr. Chunhui Zhou, Senior Manager of Pearl Identification, in this latest GIA Knowledge Session.
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October 21, 2021 | Natural Rough Diamonds: Crystal Shapes and Surface Features
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Once cut and polished, diamonds of similar size, shape and quality may look similar to the unaided eye. But in their rough form, natural diamonds have distinctive morphologies that tell much about their formation and their volcanic journey to Earth’s surface. Natural diamonds can form as glassy octahedral crystals, flat macles, in unusual spherical shapes and more. During their volcanic transit up to Earth’s surface, they also often acquire intricate markings from corrosive fluids. Tune in as GIA Research Scientist Dr. Evan Smith unravels the story behind rough diamonds’ unique morphologies.
September 16, 2021 | Identification of Paraíba Tourmaline in GIA Laboratories
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“Paraíba tourmaline” took the design world by storm due to its striking “neon” glow when it was first discovered in Paraíba State, Brazil. Today, GIA laboratories evaluate Paraíba tourmaline along four factors: species classification, color, treatments and origin. Origin is an important determiner of Paraíba tourmaline’s value because, even though similarly colored tourmalines have been discovered in other parts of the world, Paraíba tourmaline found in Paraíba is often more sought-after. Tune in as GIA Carlsbad Research Associate Ziyin Sun breaks down the factors that determine the quality and value of this mesmerizing gemstone.
August 12, 2021 | The Science of Colored Diamonds
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Colored diamonds exist in a rainbow of colors, from red and pink to green, blue, purple and brown. Created through a variety of factors, such as exposure to radioactive fluids or minerals, or trace elements getting trapped in the diamond’s crystal lattice, they are rare and priceless marvels of nature, existing as a result of extraordinary geologic occurrences. Tune in as GIA Senior Manager of Diamond Identification Dr. Sally Magaña dives into the science of colored diamonds and how these treasures are created deep within the earth.
July 15, 2021 | A Review of Spinel: Treatment and Geographic Origin
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Spinel, sometimes referred to as "History's Most Underappreciated Gem," was often confused with ruby and sapphire. What are the latest discoveries of this unique gemstone in modern gemology? Follow GIA Hong Kong Supervisor of Identification (Colored Stone) Xiaodan Jia as she dives into the gemologcial characteristics and major sources of spinel.
May 20, 2021 | GIA iD100™: Quickly and Easily Distinguish Natural from Laboratory-Grown Diamonds
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Want to know a fast and accurate way to distinguish natural diamonds from laboratory-grown diamonds and diamond simulants? Discover how the GIA iD100™ uses fluorescence spectroscopy combined with automatic spectral analysis algorithms to screen loose and mounted diamonds. This cutting-edge device can be used to distinguish D to J colorless diamonds and can also detect multi-treated pink diamonds. Join as Senior Research Scientist of Instrument Development Dr. Tsung-Hang Tsai explores the optical spectroscopic and imaging techniques that GIA scientists use to analyze diamonds on a daily basis and that are also incorporated in the GIA iD100™.
April 22, 2021 | Laboratory-Grown Diamonds in China, their Treatments and Associated GIA Services
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Dr. Ulrika D’Haenens-Johansson, Senior Manager of GIA Diamond Research, and Dr. Wei Li, of Chongqing Daimeng Youshi Technology Co., Ltd., will review the progress on laboratory-grown diamonds in China. Dr. Li will share his expertise on their treatment, revealing how it is possible to create beautiful laboratory-grown diamonds spanning the full rainbow of colors. They will also discuss associated GIA services that support the confident and transparent purchase of laboratory-grown diamonds, such as the recently updated Laboratory-Grown Diamond reports.
February 18, 2021 | GIA - 90 Years of Innovation
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Established in 1931, GIA marks its 90th anniversary this year. In our almost century-long history, we created the 4Cs of diamond quality and the GIA International Diamond Grading System™, and developed pioneering instrumentation for diamond grading. What scientific breakthroughs led GIA to where it is now, and what’s next? Join Dr. Wuyi Wang, GIA’s vice president of research and development, as he explores 90 years of innovation in diamond grading and identification, and instrument development, followed by his predictions for the challenges and opportunities ahead.
January 21, 2021 | GIA Research — Not Just for Scientists
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Ever wonder who plans GIA courses and what goes into them? Gemology is part science, part art, part business. That’s why our education is fueled by GIA research — including our unique field gemology explorations — as well as informed by the information and experience of people throughout the industry. Whether you are a GIA alum or are simply curious about GIA education, tune in to “GIA Research — Not Just for Scientists” presented by Dr. Tao Hsu — Director of Global Professional Development — to get a behind-the-scenes look at how we design our world-respected curriculum.
December 10, 2020 | Diving into the GIA 7 Pearl Value Factors™
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While diamonds have four primary areas of assessment (the 4Cs), pearls have seven! These include size, shape, color, nacre, luster, surface and matching. Evaluating pearl’s enchanting beauty can be quite complex. Did you know that in addition to bodycolor, some pearls also have overtone and orient? That’s why GIA has developed a systematic technique for evaluating pearls. Follow GIA Senior Manager of Pearl Identification Dr. Chunhui Zhou as he explores the GIA 7 Pearl Value Factors™ and its recent updates and introduces the new Cultured Pearl Classification Report.
November 12, 2020 | Understanding “Fei Cui”: Jade Identification and Nomenclature
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Jade is the most valuable translucent to opaque gem, and GIA as well as the modern market has established unique standards for evaluating its quality. What’s the difference between ‘jade’ and ‘fei cui’ and what do the terms “A Jade”, “B Jade” and “C Jade” mean in the trade? Tune in as Senior Staff Gemologist Xiaodan Jia from GIA Hong Kong covers the history, identification, treatments and nomenclature of this precious gem from an international gemological perspective.
October 15, 2020 | Treatments in Corundum
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Rubies and sapphires are some of the most sought-after gems in the world. As a result, a wide variety of methods have been invented to treat them for color and clarity. Common treatments include assemblage, oil filling, dying, glass filling, lattice diffusion, heating and irradiation. What are the telltale signs of treated corundum? And how do GIA gemologists detect these treatments? Follow GIA Carlsbad Research Associate, Ziyin Sun, as he covers crucial knowledge to unmasking treatments in these beloved gems.
September 17, 2020 | Laboratory-Grown Diamond Identification
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In recent years, laboratory-grown diamonds have been produced in commercial quantities and qualities and are being used more and more in jewelry. Impossible to distinguish from natural diamonds with the unaided eye, laboratory-grown diamonds can only be detected through advanced analysis by a gemological lab. Tune in as GIA Vice President of Research and Development Wuyi Wang talks in-depth about laboratory-grown diamonds, including post-growth treatments and the identification methods used to detect these gems.
August 20, 2020 | A Closer Look at Sapphire: Treatment and Geographic Origin
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Sapphire has been cherished for thousands of years for its remarkable color, luster and hardness. What are the most popular modern treatment processes and how do they improve the appearance or durability of a sapphire? Where are sapphires mined and how do scientists track their provenance through inclusion study and advanced testing? Tune in as Jia Xiaodan, Senior Staff Gemologist of Colored Stones at GIA Hong Kong Laboratory, shares the most recent developments on sapphire treatments and origin determination.
August 6, 2020 | Major Gem Producing Areas Around the Globe
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The world’s most productive gem sources are constantly changing. Old mines dry up while new ones are found. What are currently the most productive big three (ruby, emerald and sapphire) mines? Where are the best Paraiba tourmaline found? Fueled by data collected from 95 GIA field gemology expeditions to 21 countries, Director of Global Professional Development, Dr. Tao Hsu, offers an overview tour of the world’s most famed and productive gem sources.
July 23, 2020 | An Overview on Pearl Identification: Techniques and Challenges
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The nacreous and non-nacreous layers that make up a pearl offer many clues to the gem’s origin. How do we know if a pearl is natural or cultured, saltwater or freshwater and what mollusk created it? Furthermore, how do we detect treatments? GIA Manager of Pearl Identification Dr. Chunhui Zhou dives into pearl identification methods. From simple observation to x-ray radiography and DNA barcoding, learn how and why GIA scientists analyze pearls.
July 9, 2020 | Advanced Analytical Techniques
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Gemology has come a long way as a field since its start in the early 1900s. Initially, gemology’s question was: “what is this stone?” Then: “is this stone laboratory-grown or natural?” and then “has this stone been treated?” Now, the all-consuming question is: “which country is this stone from?” As the industry evolves and our knowledge expands, so does our desire to learn more. That’s why advanced analytical techniques have become indispensable to modern gemology. Tune in as GIA research associate, Ziyin Sun, explores the instruments and techniques used to address gemology’s most pressing questions.
June 23, 2020 | The Fascinating World of Pearls and Shells
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We’re shelling out pearl knowledge with a webinar by GIA Manager of Pearl Identification Dr. Chunhui Zhou. Do all bivalves, including oysters, clams and mussels, produce pearls? What are conch and melo pearls? Which pearl types are the most popular and where are they found? From the seas of Australia, Tahiti and Thailand to the waters of China, travel with us as we dive into the world of these rare organic treasures.
June 11, 2020 | An Exclusive View of the World’s Biggest Jade Auction
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Jadeite is the only colored gemstone whose auction price can rival that of ruby, emerald and sapphire. What is jadeite’s enduring appeal and what factors determine this gem’s value? Journey with Dr. Tao Hsu, geologist and director of global professional development for GIA education, as she explores a jadeite auction at the exclusive Myanma Gems Emporium in Myanmar — the country that produces over 90% of the world’s jadeite. Pick up insider tips and knowledge along the way!
May 28, 2020 | Laboratory-Grown Diamonds from China
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China is the world’s largest producer of laboratory-grown diamonds for industrial use and is now a significant producer of gem-quality laboratory-grown diamonds. What role does China play in the laboratory-grown diamond market and what impact does it have on the natural diamond market and the jewelry industry? Find out as Dr. Wuyi Wang, GIA vice president of research and development, breaks down how and why laboratory-grown diamonds are produced in the world’s second-largest economy.
Other GIA Virtual Events
Past GIA Tokyo GemFests (Japanese)
January 6, 2021 | 29th Tokyo GemFest: The Gemological Characteristics and Earth Science of Jadeite
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Jadeite has been prized in Asia, South America and Central America since ancient times, and it is presently well-known as one of the most popular gemstones. Recent scientific researches on jadeite also suggest that jadeite is the key to understanding the evolutionary history of the Earth. In this seminar, we will introduce the basic gemological characteristics of jadeite, including Japanese jadeite, and its importance on Earth science.
December 10, 2020 | 28th Tokyo GemFest: Recent Colored Stone Market Trends in Japan
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Recently, rare and interesting colored stones are gaining popularity in the domestic market. In this seminar, Mr. Oyama will explain and analyze the market trends of the all-time famous colored stones but also the colored stones that are recently gaining popularity in Japan.
November 25, 2020 | 27th Tokyo GemFest: How to Transform a Basic Jewelry Brand into a Luxury Brand
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In this presentation, Dr. Shinya Nagasawa, Professor of Waseda University, will explain and share his long-time research on luxury branding and marketing. He will share his view of how to transform Japanese jewelry brands into global luxury brands to make them competitive.
October 15, 2020 | 26th Tokyo GemFest: Ethics and Sustainability of the Jewelry Industry
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Recently, terms such as “sustainable” and “ethical” have become popular in the fashion industry. As millennials emerge as major consumers, ethics and sustainability will also become important in the jewelry industry. This presentation focuses on the global movement towards ethics and sustainability within the jewelry industry by introducing concepts that HASUNA uses in its brand.
October 9, 2020 | 25th Tokyo GemFest: Advanced Analytical Equipment Used in GIA Laboratories
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In recent years, there have been great advancements in gem identification techniques. Standard gemological tools are not always effective when identifying treated stones and laboratory-grown gems, or when determining geographic origins. Highly advanced analytical techniques used to determine concentrations of trace elements are now necessary for origin determination. This seminar discusses how GIA's laboratories have progressed by using new analytical techniques.
September 30, 2020 | 24th Tokyo GemFest: Understanding CVD Diamond – Its History and Application
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Diamonds grown by chemical vapor deposition synthesis, known as CVD, are relatively new to the market and have attracted recent attenion. Japan developed CVD synthesis for diamonds in the early 1980s and has since been a global leader in CVD diamond research. In this seminar, Dr. Tsugawa, who been involved in CVD diamond research for years and currently works for the world-leading manufacturer of diamond CVD systems, will discuss the history and the current applications of CVD synthesis for diamonds.
August 19, 2020 | 23rd Tokyo GemFest: Extraterrestrial Gems: Attraction of Meteorites
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Meteorites are visitors from space whose origins are asteroids. They formed 4.56 billion years ago when our solar system was born. Some rare meteorites came from the Moon and Mars. In this seminar, Dr. Mikouchi will talk about the attraction of meteorites from the viewpoints of their mineral beauty and the hidden history of the birth of the solar system and its evolution.
July 8, 2020 | 21st Tokyo GemFest: Identification and Treatments of Colored Stones
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The treatments of colored stones during the gem and jewelry trade process are carried out to improve the appearance and color of gemstones. Such treatments include heat treatments of ruby and sapphire, clarity enhancements of emerald, and a combination of bleaching and dying of jade. During this presentation, the types of colored stone treatments and identification methods will be introduced.
June 17, 2020 | 20th Tokyo GemFest: Geographic Origin Determination of Ruby
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Ruby is produced in a variety of localities, ranging from Southeast and Central Asia (including Myanmar), to East Africa. This seminar will introduce GIA's efforts in geographic origin determination and will share the latest findings on rubies.
May 29, 2020 | 19th Tokyo GemFest: Geographic Origin Determination of Paraíba Tourmaline
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Blue to green copper-bearing tourmaline, known as Paraíba Tourmaline, has been quite popular in the colored gemstone market for the past three decades. This seminar will review its gemological characteristics and discuss GIA’s geographical origin determination.
May 21, 2020 | 18th Tokyo GemFest: Laboratory-Grown Diamonds Basics and Updates
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Recently, we are seeing an increase in laboratory-grown diamonds used in jewelry. In this seminar, we explain the synthesis methods and the characteristics of laboratory-grown diamonds that are useful for identification. We also introduce some of the latest laboratory-grown diamonds examined at GIA.
May 8, 2020 | 17th Tokyo GemFest: Gemological Characteristics and Origin Identification of Alexandrite
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Alexandrite is a famous gemstone that shows a beautiful color change effect. In this seminar, we introduce the basic gemological characteristics of alexandrite and GIA’s Identification and Origin Report service which started in early 2019.
Past GIA Gemstone Gatherings
September 23, 2020 | Traditional vs. Non Traditional Color Terms Applied to Sapphires
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Over the past five years, the sapphire market has seen an uptick in demand for two hue ranges seen in sapphires — rO-oY(peach) and bG-gB (teal). This session will give attendees the tools to understand and articulate clearly to their customers the subtle differences between pinkish-orange, orangish pink, and Padparadscha stones. Sheahan will also give clear-cut descriptions for G (green), bG-gB (teal), and yellow-green sapphires. Through reviewing a number of graphs covering time, color, consumption, and shifting prices, attendees will gain an in-depth understanding of what’s causing this movement toward fancy-colored sapphires from traditional blue stones. Ultimately, this session will help attendees understand their customers’ requests/needs more clearly and help them close sales on these unique, fancy-colored sapphires.
June 24, 2020 | 115th Gemstone Gathering: Precision Cut: How, Why and When?
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The expression “precision cut” has become very popular over time. Victor Tuzlukov will explain his point of view on the term "precision cut" and share his inspirations that led him to become a professional cutter. He will also lead a discussion on the advantages and disadvantages of the precision cut, how such lapidary work affects the gemologist, and how to judge whether existing fashioned stones would benefit from re-cutting.
