Summer 2018 Gems & Gemology: Scintillating with Gemstone Colors
New feature “Diamonds from the Deep” shows the importance of natural diamond in scientific research
CARLSBAD, Calif. – Aug. 13, 2018 – In the Summer 2018 issue of Gems & Gemology (G&G), researchers review more than 15,000 natural blue diamonds to find the cause of their color, examine alluvial black diamonds containing radioactive minerals, and uncover the journey of a Byzantine garnet from the southeast Indian shore to the Mediterranean along the historic Maritime Silk Road. GIA’s quarterly professional journal also presents cultured pearls from Lake Kasumigaura, Japan; the vibrant gems from the Yogo sapphire deposit; an in-depth wall chart on synthetic diamonds; and a new regular feature called “Diamonds from the Deep.” This issue is now available in print and online.
The summer issue starts off with “Natural-Color Blue, Gray, and Violet Diamonds: Allure of the Deep,” where GIA researchers Sally Eaton-Magaña, Christopher M. Breeding and James E. Shigley review the science of natural blue diamonds. Using data collected from more than 15,000 samples examined by GIA, these researchers were able to provide a unique description of one of nature’s rarest and most valuable gems.
GIA’s Karen V. Smit, Elina Myagkaya, Stephanie Persaud and Wuyi Wang follow with “Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions.” This study investigates the color origin of 40 natural Fancy Dark brown-black round brilliant diamonds from the Marange alluvial deposits in eastern Zimbabwe. Visual observations show that the dark appearance of the diamonds is due to a combination of methane-associated graphite inclusions, graphite needles, and dark brown radiation stains that are likely related to their billion-year residence in the Umkondo conglomerate.
In G&G’s third feature, H. Albert Gilg, Karl Schmetzer and Ulrich Schüssler share the story of how an early Byzantine almandine garnet engraved with a Christian motif and dating to the late sixth to the eighth century offers insight into ancient trade practices. In the fourth paper, Ahmadjan Abduriyim investigates Japanese “Kasumiga pearl” culturing and describes the quality and production volume.
GIA authors Nathan D. Renfro and Aaron C. Palke, with Richard B. Berg, offer a complete gemological characterization of sapphires from Yogo Gulch, Montana. This is one of the most important sapphire deposits, known for gemstones with vibrant untreated blue color and high clarity. The last feature article in this issue is Sally Eaton-Magaña and Christopher M. Breeding’s new wall chart on the growth and characteristics of high-pressure, high-temperature (HPHT) and chemical vapor deposition (CVD) synthetic diamonds, including recent technological advancements that enabled larger sizes and better quality.
This issue also presents a new regular column by Karen Smit and Steven Shirey, “Diamonds from the Deep,” that examines the importance of natural diamond in scientific research. The first installment reveals how diamonds are helping researchers understand the presence of water in the earth’s depths.
The regular Lab Notes, Micro-World and Gem News International sections round out the issue. Lab Notes include a beryl and glass assemblage imitating emerald, plus the latest developments in synthetic diamonds. Gem News International highlights a unique green-blue Maxixe-type beryl, trace-element characteristics of “golden sheen” sapphire and the discovery of color-change chrome garnets in Ethiopia. Micro-World features mushroom preserved in copal, microlite crystals in topaz and a wurtzite phantom in quartz.
This and every issue of G&G since 1934, including full articles, lab notes, photo galleries and exclusive video footage, is available at no cost on GIA’s website at GIA.edu/gems-gemology.
Additional research articles are available at GIA.edu/gia-news-research.
Print subscriptions and copies of back issues are available at http://store.gia.edu/, or by contacting G&G customer service at +1 760-603-4502.
