Historical Reading List: Mediterranean Precious Coral

Dr. James Shigley

For more than two millennia, the hard skeleton of red or pink marine coral from the eastern Mediterranean has been sought after and then manufactured as a valuable material for personal adornment and other purposes.  Due to its attractive intense color, glossy appearance when polished, and durability, its use and popularity (dating back to both ancient Egypt and prehistoric Europe) continues to the present day.

In earlier times there was some uncertainty whether marine coral was a mineral, a plant or an animal because it was thought to display features of each.  This confusion was settled by the work of the French naturalist Jean-André Peyssonnel who, based on studies in the Mediterranean, found that living corals are animals, and who first published these findings in 1726.

Red corals grow in warm and clean waters in branched colonies up to about one meter in height on the rocky sea bottom in environments with low light levels – typically at depths from 10 to 300 meters below the surface.  The original species, Corallium rubrum, occurs mainly in the Mediterranean Sea and along the nearby Atlantic coast.  Other red coral species are found in the central and western Pacific.  The coral skeleton is composed of intermeshed spicules of calcium carbonate – the red coloration is due to the presence of carotenoid pigments.  In living specimens, the hard skeletal branches are overlain with a soft, bright red outer protective layer from which numerous retractable white polyps protrude.  It is these skeletal branches that are used as gem material.

In the first millennium, there was significant trade in red coral between the Mediterranean area and the East, where the material was prized because it was thought to be endowed with religious, mystical and medical curative powers, particularly in China and India.  The economic importance of red coral was mentioned by Pliny the Elder and other ancient writers.  Working along the shore, individuals from small boats would dive down and recover the coral.  From the Middle Ages onward, there was a considerable rivalry at times among communities along the western Mediterranean to secure commercial control of the coral fisheries off the European and North African coasts.  Over the past three centuries, manufacturing of red coral for jewelry use has been centered in coastal towns in southern France and western Italy.  Until modern times, intensive fishing particularly in shallow waters has periodically threatened the survival of red coral species along the Mediterranean coastline, but recent conservation efforts have resulted in areas where there is red coral restoration.  In 1994, the use of drag-nets was banned, and since that time, Mediterranean coral harvesting is only done by scuba divers.

There are currently no restrictions on the international trade in red coral.  While Corallium rubrum corals are not included within the requirements of the Convention on International Trade in Endangered Species (CITES), similarly colored Stylaster corals are listed in Appendix II of this treaty (which covers species not necessarily faced with extinction, but it requires trade in these species to be controlled to insure their survival).  A practical problem remains to distinguish pink-to-red coral of different coral species.

HOW TO USE THIS READING LIST

This reading list was compiled to give you an opportunity to learn more about the history of Mediterranean Precious Coral. A number of the articles were published in the 1800s and early 1900s – when many classical gem deposits of historical importance were discovered – and gemology and mineralogy became sciences. The list is presented in chronological order to emphasize the development of ideas over time. The list is not comprehensive, but a compilation of the some interesting gemological information that has often been forgotten or overlooked.

Many of the articles exist in the public domain and can be found online at digital libraries such as Hathitrust, Internet Archive, or other digital repositories. More recent publications can often be found in libraries, including the Richard T. Liddicoat Gemological Library. Abstracts of these articles can usually be found on the website of the original journal or magazine, and the article itself is often available for purchase from the publisher.

Regarding the GIA library’s holdings and on-site access, please contact the GIA library in Carlsbad.

“Recherches et Observations Naturelles [Nature Research and Observations]”, P. Boccone, Chez J. Jansson à Waesberge, Amsterdam, 328 pp., (1674).  The first portion of this book contains letters from several authors that discuss various aspects of Mediterranean corals.

Several Microscopical Observations on the Pumice-Stone, Coral, Sponges, et cetera, A. Van Leuwenhoek, Philosophical Transactions of the Royal Society of London, Vol. 24, pp. 2158-2163, (1705).  In this article, the famous Dutch scientist who made major improvements to the microscope describes the micro-structure of coral and other porous natural materials and offers ideas on their formation.

Microscopical Observations on Red Coral, A. Van Leuwenhoek, Philosophical Transactions of the Royal Society of London, Vol. 26, No. 315, pp. 126-134, (1708).  The author, the inventor of the microscope, makes observations on the structure of red coral, and he describes some experiments that he made on the material.

Sur les Analyses du Corail [On the Analyses of Coral], C.J. Geoffroy, Histoire de l’Académie Royale des Sciences, pp. 102-105, (1708).  The author discusses the work of several individuals who had investigated red coral and its coloration.

Sur le Corail [On the Coral], Author unknown, Histoire de l’Académie Royale des Sciences, pp. 45-48, (1711). A discussion of the work on several researchers on coral.

Sur la Formation du Corail… [On the Formation of Coral], R.A.F. de Reaumur, Histoire de l’Académie Royale des Sciences, pp. 378-396, (1727). The author reviews the state on knowledge of coral and its formation.

“Principales Merveilles de la Nature” [Principal Wonders of Nature], L. de Mailly, R. Machuel, Rouen, Pt. 2, pp. 312-316, (1728).  This book describes a number of natural wonders, including a short discussion of coral.

On the Growth of Coral, F. Bacon, “The Works of Francis Bacon”, London, Vol. 3, Sec. 8, p. 159, (1740).  A brief description by the famous English philosopher and scientist (1561-1626) of coral from the waters off of Sicily which, when underwater, is “soft and green of color, but being brought into the air, it becometh hard and shiny red…”.

New Discoveries Relating to the History of Coral, V. Donati and T. Strack, Philosophical Transactions of the Royal Society of London, Vol. 47, pp. 95-108, (1751).  An early, more detailed description is given of the structure of corals.

A Treatise upon Coral, J.B. Peyssonnel, Philosophical Transactions of the Royal Society of London, Vol. 47, pp. 445-469, (1751).  The author discusses his earlier work that established that corals are living animals.

A Letter from James Parsons Concerning the Formation of Corals, Corallines, et cetera, J. Parsons, Philosophical Transactions of the Royal Society of London, Vol. 47, pp. 505-513, (1751).  Beginning from the work of Peyssonnel, the author discusses further observations that support the idea that corals are living animals.

Sur le Description d’une Machine propre à Pêcher le Corail, … [Description of a Machine to Clean and Fish for Corals,…], J.J. Béraud, Observations sur la Physique, sur l’Histoire Naturelle et sur les Arts, Vol. 41, pp. 21-29, (1792).  In response to a financial prize offered by the Academie of Marseille, the author describes a device for harvesting coral.

On the Coral Fishery in the Sicilian Seas, A. Ferrara, Journal of Natural Philosophy, Chemistry and the Arts, Vol. 33, (October), pp. 136-145, (1812). Having visited the Sicilian fishery, the author discusses ideas expressed by previous authors on the nature of coral.

Die Korallen, deren Gewinnung und deren Verarbeitung zum Schmuck [The Corals, their Recovery and their Manufacturing for Jewelry], Author unknown, Bulletin des Neuesten und Wissenswürdigsten aus der Naturwissenschaft, Vol. 13, pp. 309-321, (1813). A review is presented of the methods used to recover Mediterranean precious coral and its manufacture for jewelry use.

Analytische Versuche über die rothen Corallen [Analytical Experiments on the Red Coral], A. Vogel, Journal für Chemie und Physik, Vol. 18, No. 2, pp. 146-156, (1816). The author presents results of an early chemical analysis of this material.

On Coral and the Coral Fishery, Author unknown, Penny Magazine, Vol. 9, No. 507, pp. 79-80, (1840). A description is given of coral and how it is recovered and manufactured in the Mediterranean for jewelry use.

The Curiosities of Commerce – The Coral Fishery, Author unknown, Merchant’s Magazine and Commercial Review, Vol. 16, pp. 62-64, (1847).  The coral fishery in the Bay of Naples is described.

A Few Words on Corals, Author unknown, Sharpe’s London Magazine, Vol. 11, pp. 284-286, (1850).  General information is given on corals.

Sur la Pêche du Corail en Algérie [On the Algerian Coral Fishery], J.B.P. Vaillant, Bulletin Mensuel de la Société Impériale Zoologique d’Acclimatation, Vol. 2, No. 4, pp. 177-192, (1855), and Rapport sur les Questions Relatives au Corail [Report on Questions Related to Coral], A. Focillon, Bulletin Mensuel de la Société Impériale Zoologique d’Acclimatation, Vol. 3, No. 5, pp. 213-222, (1856).  The important coral fishery along the coast of Algeria is described in these two articles.

The Coral of Commerce, P.L. Simmonds, The Technologist, Vol. 2, No. 1, pp. 20-24, (1861), and The Coral Fishery of the Mediterranean, The Technologist, Vol. 3, pp. 372-378, (1863).  Because of an increasing use of coral ornaments in fashion, the author in these two articles gives a description of coral, where it is found, and how it is recovered from coastal waters.

“Histoire Naturelle du Corail” [The Natural History of Coral], F.J.H. de Lacaze-Duthiers, Baillière, Paris, 367 pp., (1864). A detailed study of the Mediterranean coral industry published by a French marine biologist.

Recent Investigations into the Natural History of the Red Coral, H. Lawson, Popular Science Review, Vol. 4, pp. 67-76, (1865).  The author reviews the structure and biology of coral, and he describes the Mediterranean precious coral industry.

Jewels of the Deep – Coral, S. de Vere, Putnam’s Magazine, Vol. 1, (January), pp. 25-33, (1868). A detailed description of the Mediterranean coral fisheries is given in this article.

Coral and the Coral Fishery, Author unknown, Leisure Hour, Vol. 17, No. 5, pp. 301-302, (1868).  A brief description of the coral fishery along the coast of Algeria is presented.

De la Pêche du Corail [The Coral Fishery], Author unknown, Bulletin de la Société Nationale d’Acclimatation, Vol. 6, pp. 10-19, (1869).  A review is given of the Mediterranean coral trade.

Corals and Their Polypes, M. Duncan, The Student and Intellectual Observer, Vol. 3, No. 1, pp. 81-91 and No. 4, pp. 241-250, (1869), and Vol. 4, No. 2, pp. 95-107 and No. 4, pp. 445-456, (1870). In this series of articles, the author discusses the history of the scientific study of corals.

Die Korallenfischerei im Mittelländischen Meere [The Coral Fishery in the Mediterranean Sea], Author unknown, Aus der Natur, Vol. 53, No. 28, pp. 445-447, (1870).  A brief description is given of the coral fishery.

On the Pearl, Coral and Amber Fisheries, P.L. Simmonds, Journal of the Society of Arts, Vol. 18, No. 896, pp. 173-183, (1870).  The author describes the commercial products of marine fisheries, including the pearl beds found along the coasts of Algeria, Corsica, Italy and Sardinia.  A summary of this article, under the title Gems of the Sea, appeared in Chambers’s Journal, Vol. 47, No. 334, pp. 325-327, (1870), and in the Eclectic Magazine, Vol. 2, (September), pp. 172-175, (1870).

L’Industrie Coralline en Italie [The Italian Coral Industry], Author unknown, Revue Maritime et Coloniale, Vol. 34, pp. 956-957, (1872). A brief description is given of the Italien coral trade.

Pêche du Corail [Coral Fishery], Author unknown, Revue Maritime et Coloniale, Vol. 35, pp. 724-727, (1872). The author discusses the Mediterranean coral trade in Italy and Algeria.

Über die Corallin [About the Corals], H. Fresenius, Journal für Praktische Chemie, Vol. 5, No. 3/4, pp. 184-197, (1872).  This article discusses early results of the chemical analysis of corals.

Corals, E.M. Mitchell, Arthur’s Illustrated Home Magazine, Vol. 41, No. 12, pp. 756-758, (1873).  Some general information is given about corals and the Mediterranean fishery.

The Coral and Its Builders, Author unknown, Frank Leslie’s Pleasant Hours, Vol. 18, No. 1, pp. 62-63, (1875).  The Mediterranean coral fishery is briefing described.

La Pêche du Corail sur les Cotes de l’Algérie [The Coral Fishery along the Coast of Algeria], C. de Cuverville, Revue Maritime et Coloniale, Vol. 45, pp. 404-443 and 657-687, (1875). A detailed report on the coral fishery along the coast of Algeria.

Le Corail [The Coral], A.L.E. Bitard, Le Monde des Merveilles, pp. 113, 121-123, (1878).  The author gives a short summary of coral and the coral fisheries.

“The Commercial Products of the Sea”, P.L. Simmonds, Griffith and Farran, London, pp. 436-462, (1879).  This book contains a detailed chapter on corals and the coral fisheries.

Precious Coral, H.N. Moseley, Nature, Vol. 25, No. 648, pp. 510-511, (1882). A brief description is presented of the Italian coral industry.  The same article appeared that year in Littell’s Living Age, Vol. 153, No. 1975, pp. 255-256.

Le Corail Rouge [The Red Coral], A. Bitard, Les Merveilles de l’Ocean, pp. 205-214, (1883).  The author reviews the history of studies of Mediterranean precious coral.

Italian Coral Industry, Author unknown, Journal of the Society of Arts, Vol. 32, No. 1644, pp. 681-682, (1884). Information is presented on the size of the Italian coral industry, with the fisheries centered near the islands of Corsica, Sardinia and Sicily, and along the coast of Algeria, and with coral manufacturing based mainly in the town of Torre del Greco near Naples.

Italian Coral Industry, Author unknown, Frank Leslie’s Popular Monthly, Vol. 19, No. 4, p. 503, (1885). A few details are given for the coral industry.  The quantity of coral collected annually is approximately 78,000 kilograms – mainly along the coasts of Algeria, Italy, Spain and Tunisia.

La Pêche du Corail [The Coral Fishery], H. Lacaze-Duthiers, L’Afrique – Choix de Lectures de Géographie, pp. 157-167, (1885). The coral fishery along the Algerian coast is described.

Coral Fishing, Author unknown, Littell’s Living Age, Vol. 55, No. 170, pp. 251-253, (1886).  One of the centers of the Mediterranean coral trade was the area around Naples in Italy.  This article describes many aspects of the coral industry.  The value of coral depends on its color and size, with the white or rose-tinted varieties standing highest in popular esteem followed by the bright red variety.  To recover the coral branches, a cross is constructed of two heavy wooden beams to which hempen nets are attached.  The cross is moved up and down against rocks along ocean bottom, and the coral branches are caught in the nets.  The most productive areas lie at depths between 75 and 150 meters below the surface.

Coral Fishery, Author unknown, Scientific American Supplement, Vol. 22, No. 563, pp. 8996-8997, (1886). A brief summary is given of the Italian coral fishery.

Coral Fishing, Author unknown, Eclectic Magazine, Vol. 107, No. 4, pp. 485-487, (1886).  The Mediterranean coral fishery is described.

The Coral Industry, Author unknown, Chambers’s Journal, Vol. 67, No. 332, pp. 303-304, (1890).  According to the British counsel in Naples, the local coral fisheries are in decline because of diminishing supplies.  The success of underwater diving bells and mechanical devices, which replaced divers to harvest the coral, may have hastened this decline.

The Italian Coral Industry, Author unknown, Journal of the Royal Society of Arts, Vol. 42, No. 2174, pp. 742-743, (1894).  The principal Italian ports for the coral trade are Genoa, Leghorn (Livorno), and Naples (with the latter being also the main manufacturing center).  The summer months – March to October – are the period when coral is recovered along the coasts of Sicily and Sardinia.  Depending on the size and color, the coral branches are manufactured as beads or other objects.

La Pêche et le Commerce du Corail en Italie [The Fishery and Commerce of Coral in Italy], G. Hütterott, Revue Maritime et Coloniale, Vol. 120, pp. 198-206, (1894). A summary of a report on the Italian coral industry.

Le Pêche du Corail en Algérie [The Coral Fishery of Algeria], J. Layrle, La Revue Maritime, Vol. 138, pp. 177-186, (1898). The author describes the coral fishery along the coast of Algeria.

The Revival of Coral, E. Bee, Jewelers’ Circular Weekly, Vol. 39, No. 2 (August 9), pp. 7, 9, (1899).  The author discusses the revival of interest in coral in jewelry and other ornaments.

Precious Coral, O.C. Farrington, Birds & Nature, Vol. 13, No. 2, pp. 79-80, (1903).  General information on coral is presented.

Precious Corals, S.J. Hickson, Annual Report and Transactions of the Manchester Microscopical Society, Vol. 26, pp. 29-38, (1905).  In this article, which is the summary of a lecture given to the society, the author gives the history of the use of coral, its biological anatomy, and its geographic distribution.

La Pêche du Corail sur les Cotes du Quartier de Saint-Tropez [The Coral Fishery of the Coast near Saint Tropez], J. Cablat, La Revue Maritime, Vol. 166, pp. 99-116, (1905). A report on the coral industry along the French coast of the Mediterranean.

“Les Compagnies du Corail” [The Coral Companies], P. Masson, Imprimerie Barlatier, Marseille, 254 pp., (1908). This book describes the history of the Mediterranean coral fisheries off the coasts of France and Algeria.

Die Österreichische Korallenfischerei [The Austrian Coral Fishery], A. Steuer, Urania – Wochenschrift für Volksbildung, Vol. 5, No. 34, pp. 604-605, (1912). A brief description is given of the coral fishery in the Adriatic Sea.

Coral Production in Italy, Author unknown, Journal of the Royal Society of Arts, Vol. 65, No. 3378, p. 670, (1917).   A summary is presented of the Italian coral trade, including details of the method of polishing the coral.

The Coral Trade in Italy, Author unknown, Jewelers’ Circular-Weekly, Vol. 74, No. 23, p. 59, (1917).  The hazards of oceanic transport during World War I resulted in difficulty for American coral manufacturers and retailers to obtain material from Italy.

A Word about Coral and Shell Cameos and How They are Cut in Italy, G. Vilelli, Jewelers’ Circular Weekly, Vol. 82, No. 18, pp. 73, 75, (1921).  The manufacturing of cameos in Italy for personal adornment is described.

Coral: Its Occurrence and Collection, J.F. Halford-Watkins, Gemmologist, Vol. 13, No. 153, pp. 39-41, No. 154, pp. 47-49, and No. 155, p. 55, (1944).  General information is given on gem corals.

Coral, J. Walton, Gemmologist, Vol. 17, No. 202, pp. 107-118, (1948).  The author provides general information on corals.

Coral – The Forgotten Gem, L.L. Copeland, Gems & Gemology, Vol. 6, No. 9, pp. 282-287, (1950).  General information is given on gem corals.

Noble Coral – Gems of the Mediterranean, H.H. Cox, Lapidary Journal, Vol. 7, No. 6, pp. 494-502, (1954).  The author discusses the Mediterranean coral industry.

The Story of Red Coral, B.H. Rohde, Lapidary Journal, Vol. 17, No. 6, pp. 592-593, (1963).  This article contains general information on gem red corals.

The Precious Coral of the Mediterranean Sea, R.H. Ruzic, Lapidary Journal, Vol. 23, No. 5, pp. 706-710, (1969).  The author discusses the Italian coral industry.

Coral, B. Jones, Rock & Gem, Vol. 8, No. 5, pp. 64-71, (1978).  General information is given on gem corals.

Natural Coral and Some Substitutes, R. Aliprandi, F. Burragato, and G. Guidi, Journal of Gemmology, Vol. 18, No. 5, pp. 401-410, (1983).  The means of identification of coral substitute materials is described.

East and West: The Ancient Gem Trade between India and Rome, P. Francis, Gemological Digest, Vol. 3, No. 1, pp. 33-39, (1990).  The author discusses the major trade in gems, including red coral, that existed between the Mediterranean and India during the Classic period.

Harvesting, Predation and Competition Effects on a Red Coral Population, M. Abbiati, G. Buffoni, G. Caforio, G. Di Cola, and G. Santangelo, Netherlands Journal of Sea Research, Vol. 30, (December), pp. 219-228, (1992).  This article discusses a scientific study of the management of a coral population in the Ligurian Sea between the coasts of Italy and Corsica.

Skeleton and Sclerite Formation in the Precious Red Coral Corallium Rubrum, M.C. Grillo, W.M. Goldberg, and D. Allemand, Marine Biology, Vol. 117, No. 1, pp. 119-128, (1993).  Using microscopy and X-ray microanalysis methods, the authors investigate the formation of the coral structure.

Background Concepts for a Rotating Harvesting Strategy with Particular Reference to the Mediterranean Red Coral, Corallium Rubrum, J.F. Caddy, Marine Fisheries Review, Vol. 55, No. 1, pp. 10-18, (1993).  Based on a field study, the researchers conclude that a harvesting schedule of every 9-15 years would be optimal to maintain a sustainable red coral population.

Rosso Corallo – The Gem of the Sea, S. Rossi, Jewellery International, Vol. 38, (April/May), pp. 119-122, (1997).  Diminishing coral supplies, and a lack of young artisans who are trained to work with this material, are causing concerns in the jewelry trade for the future of the traditional coral industry in Italy.

Is CITES an Effective Tool for Monitoring Trade in Corals?, E.P. Green and H. Hendry, Coral Reefs, Vol. 18, No. 4, pp. 403-407, (1999).  CITES is an international treaty drawn up to protect wildlife populations from over-exploitation.  The authors discuss the widespread failure to record coral species on trade permits as required by this treaty.  They tested non-specialists involved in the coral trade, and found in most instances that the individuals could not correctly recognize coral species.  They suggested better identification guidelines, and a requirement to identify the type of coral in a more general way, could improve the monitoring of the coral trade as mandated by this treaty.

From Livorno to Goa and Back: Merchant Networks and the Coral-Diamond Trade in the Early Eighteenth Century, F. Trivellato, Portuguese Studies, Vol.16, pp. 193-217, (2000).  Article not seen.

On the Potential Use of Magnesium and Strontium Concentrations as Ecological Indicators in the Calcite Skeleton of the Red Coral (Corallium Rubrum), M.G. Weinbauer, F. Brandstätter, and B. Velimirov, Marine Biology, Vol. 137, No. 5/6, pp. 801-809, (2000).  The chemical analysis of these two elements in coral skeletons can provide an indication of water temperature and skeleton growth rate for red corals.

Red Coral: Conservation and Management of an Over-Exploited Mediterranean Species, G. Santangelo and M. Abbiati, Aquatic Conservation, Vol. 11, No. 4, pp. 253-259, (2001).  Two red coral populations can be distinguished – small, shallow-water colonies that have been over-exploited, and larger, long-lived a deeper-dwelling populations which have been less-well studied by marine biologists.  The authors argue that a future, more-sustainable coral exploitation will require a better understanding of both groups.

Mass Mortality Event in Red Coral Corallium Rubrum Populations in the Provence Region (France, NW Mediterranean), J. Garrabou, T. Perez, S. Sartoretto, and J.G. Hamelin, Marine Ecology Progress Series, Vol. 217, pp. 263-272, (2001).  In a study of a mass mortality event in the summer of 1999 affecting red coral populations to a water depth of 30 meters, the authors suggest that a preceding period of higher water temperatures lasting for several weeks may have produced conditions which caused the mass death.

Reproduction and Population Sexual Structure of the Overexploited Mediterranean Red Coral Corallium Rubrum, G. Santangelo, E. Carletti, E. Maggi, and L. Bramanti, Marine Ecology Progress Series, Vol. 248, pp. 99-108, (2003).  This is one of the first studies of the reproductive features of the red coral.  A better understanding of this information will help to match levels of coral harvesting to population recovery rates.

Spectroscopic Characterization of Natural Corals, B. Kaczorowska, A. Hacura, T. Kupka, R. Wrazlik, E. Talik, G. Pasterny, and A. Matuszewska, Analytical and Bioanalytical Chemistry, Vol. 377, No. 6, pp. 1032-1037, (2003).  The authors present spectroscopy data on 25 different natural corals.

Demography of the Over-exploited Mediterranean Red Coral (Corallium Rubrum L. 1758), G. Santangelo, E. Maggi, L. Bramanti, and L. Bongiorni, Scientia Marina, Vol. 68, Supplement 1, pp. 199-204, (2004).  This article presents the results of a demographic study of a particular coastal red coral population to better understand the effects of coral harvesting.

A New Method for Measuring Growth and Age in the Precious Red Coral (Corallium Rubrum L.), C. Marschal, J. Garrabou, J.G. Hamelin, and M. Pichon, Coral Reefs, Vol. 23, No. 3, pp. 423-432, (2004).  A new method, involving imaging of growth rings in the coral skeleton, provides a better way to measure age and growth rate.

Precious Red Coral: Markets and Meanings, S.J. Torntore, Journal of the Society of Bead Researchers, Vol. 16, pp. 3-16, (2004).  Red coral beads are manufactured today for three principal world markets – fashion, ethnic and tourist.  The author discusses the evolution in the cultural significance of these beads over time, and describes how different beads are manufactured for each market.

Age and Size at First Reproduction in the Commercially Exploited Red Coral Corallium Rubrum (L.) in the Marseilles Area (France, NW Mediterranean), O. Torrents, J. Garrabou, C. Marschal, and J.G. Hamelin, Biological Conservation, Vol. 121, No. 3, pp. 391-397, (2005).  A study of the red coral reproduction cycle is used to develop better plans for sustaining coral populations.

Recruitment, Early Survival and Growth of the Mediterranean Red Coral Corallium Rubrum (L. 1758): A Four-Year Study, L. Bramanti, G. Magagnini, L. De Maio, and G. Santangelo, Journal of Experimental Marine Biology and Ecology, Vol. 314, No. 1, pp. 69-78, (2005).  This study of the early growth of red coral provides information on the types of colonies that have a better chance of survival.

Gem Corals – Classification and Spectroscopic Features, V. Rolandi, A. Brajkovic, I. Adamo, R. Bocchio, and M. Landonio, Australian Gemmologist, Vol. 22, No. 7, pp. 285-297, (2005), and Gem Corals – Xray Diffraction, Solid State NMR and Elemental Analysis, R. Bocchio, S. Bracco, A. Brajkovic, A. Comotti, and V. Rolandi, Australia Gemmologist, Vol. 22, No. 12, pp. 524-532, (2006).  Characterization data are presented in these two articles on samples of twenty-one different coral species.

Population Structure of an Exploited Benthic Cnidarian: The Case Study of Red Coral (Corallium Rubrum L.), G. Tsounis, S. Rossi, J-M. Gili, and W. Arntz, Marine Biology, Vol. 149, No. 5, pp. 1059-1070, (2006).  In spite of its commercial importance, the biological influences on red coral populations are little understood.  A study in the Costa Brava area of Spain found that 89% of harvested red corals are less than ten years in age, and the vast majority of coral colonies have not grown second-order branches.  The authors conclude that while red coral is still abundant, its population structure is strongly distorted by the harvesting of larger coral specimens from shallow depths.

Korallen im Edelstein- und Schmuckhandel [Corals in the Gem and Jewellery Trade], U. Henn, Zeitschrift der Deutschen Gemmologischen Gesellschaft, Vol. 55, No. 3/4, pp. 77-104, (2006).  In this article, the author discusses the history of the gem use of coral, the gemological identification of this material, current coral treatments methods, and coral imitation materials.

Red Coral Fishery at the Costa Brava (NW Mediterranean): Case Study of an Overharvested Precious Coral, G. Tsounis, S. Rossi, J-M, Gili, and W.E. Arntz, Ecosystems, Vol. 10, No. 6, pp. 975-986, (2007).  This marine study demonstrates that the historic overharvesting of red coral in shallow waters, and the underharvesting in deeper waters, has resulted in a fishery situation which is neither ecologically sustainable nor economically efficient.

Determination of Canthaxanthin in the Red Coral (Corallium Rubrum) from Marseille by HPLC Combined with UV and MS Detection, J. Cvejic, S. Tambutté, S. Lotto, M. Mikov, I. Slacanin, and D. Allemand, Marine Biology, Vol. 152, No. 4, pp. 855-862, (2007).  The authors demonstrate the presence of a particular carotene plant pigment as the major coloring agent of the red coral skeleton.

Pink-to-Red Coral: A Guide to Determining Origin of Color, C.P. Smith, S.F. McClure, S. Eaton-Magaña, and D.M. Kondo, Gems & Gemology, Vol. 43, No. 1, pp. 4-15, (2007).  The detection of dyed corals by various means is discussed in this article.

Nano-to-Microscale Biomineral Architecture of Red Coral (Corallium Rubrum), D. Vielzeuf, J. Garrabou, A. Baronnet, O. Grauby, and C. Marschal, American Mineralogist, Vol. 93, No. 11/12, pp. 1799-1815, (2008). The red coral skeleton is a composite organic/inorganic material that exhibits a hierarchical structural order on a range of length scales.

Coral Jewellery, K. Anderson, Victorian Review, Vol. 34, No. 1, pp. 47-52, (2008).  Article not seen.

Upper Thermal Thresholds of Shallow Versus Deep Populations of the Precious Mediterranean Red Coral Corallium Rubrum (L.): Assessing the Potential Effects of Warming in the NW Mediterranean, O. Torrents, E. Tambutté, N. Caminiti, and J. Garrabou, Journal of Experimental Marine Biology and Ecology, Vol. 357, No. 1, pp. 7-19, (2008).  A field study of shallow and deep red coral populations found that elevated ocean temperatures above 25°C (77°F) for a period of nine days or more resulted in mass mortality in both sample groups.  These results will help to predict the future effects of climate change on red coral populations.

Survey of Deep-Dwelling Red Coral (Corallium Rubrum) Populations at Cap de Creus (NW Mediterranean), S. Rossi, G. Tsounis, C. Orejas, T. Padrón, J-M. Gili, L. Bramanti, N. Teixidó, and J. Gutt, Marine Biology, Vol. 154, No. 3, pp. 533-545, (2008).  This quantitative study of coral populations confirms that colonies at water depths of 50 meters or less are exposed to a much high intensity of harvesting because these colonies lie within the depth limits of a diver using standard diving equipment.

Jewel of the Deep, G. Tsounis, Natural History Magazine, Vol. 118, No. 3, pp. 30-35, (2009). The author describes the decline of the traditional red coral industry in the Mediterranean, but suggests that with proper management and plenty of time, the abundance of red coral can be restored.

Pearls and Corals: Trendy Biomineralization, J.P. Gauthier and S. Karampelas, Elements, Vol. 5, No. 3, pp. 179-180, (2009).  An explanation is presented of the biomineralization process that can produce both pearls and corals.

Rate and Extent of Decline in Corallium (Pink and Red Coral) Populations: Existing Data Meet the Requirements for a CITES Appendix II Listing, A.W. Bruckner, Marine Ecology Progress Series, Vol. 397, pp. 319-332, (2009).  The author describes how existing data support the listing of red coral as a species covered by CITES.  However, the proposal to include red coral (Corallium rubrum) within this appendix of treaty was rejected.

Identification of the Endangered Pink-to-Red Stylaster Corals by Raman Spectroscopy, S. Karampelas, E. Fritsch, B. Rondeau, A. Andouche, and B. Métivier, Gems & Gemology, Vol. 45, No. 1, pp. 48-52, (2009).  A method based on Raman spectra is proposed to distinguish Corallium from Stylaster pink-to-red corals.

Experimental and Theoretical Studies on Corals, I: Toward Understanding the Origin of Color in Precious Red Corals from Raman and Infrared Spectroscopies and DFT Calculations, T. Kupka, H.M. Lin, L. Stobiński, C.H. Chen, W.J. Liou, R. Wrzalik, and Z. Flisak, Journal of Raman Spectroscopy, Vol. 41, No. 6, pp. 651-658, (2010).  Based on spectroscopic measurements and theoretical spectra calculations, the authors identify the likely pigments responsible for the vivid red color in corals.

Marine Protected Areas and the Conservation of Long-Lived Marine Invertebrates: The Mediterranean Red Coral, C. Linares, O. Bianchimani, O. Torrents, C. Marschal, P. Drap, and J. Garrabou, Marine Ecology Progress Series, Vol. 402, pp. 69-79, (2010).  The authors suggest that the use of protective ocean areas would help the recovery of endangered red coral in the Mediterranean.

The Exploitation and Conservation of Precious Corals, G. Tsounis, S. Rossi, R. Grigg, G. Santangelo, L. Bramanti, and J-M. Gili, Oceanography and Marine Biology: An Annual Review, Vol. 48, pp. 161-212, (2010).  The authors discuss the need to manage declining coral populations worldwide with a more holistic approach based on the entire local marine habitat as compared to focusing on just a single coral species.

Multilevel Modular Mesocrystalline Organization in Red Coral, D. Vielzeuf, N. Floquet, D. Chatain, F. Boneté, D. Ferry, J. Garrabou, and E.M. Stolper, American Mineralogist, Vol. 95, No. 2/3, pp. 242-248, (2010).  Based on observations at very high magnifications, the authors describe how the crystalline building blocks of the coral can be arranged into eight hierarchical levels of similarly oriented blocks.  These levels are manifest as structures in the nanometer to millimeter size range.

“Proceedings of the International Workshop on Red Coral Science, Management, and Trade: Lessons from the Mediterranean”, E. Bussoletti, D. Cottingham, A. Bruckner, G. Roberts, and R. Sandulli (editors), NOAA Technical Memorandum CRCP 13, Silver Spring, Maryland, 233 pp, (2010).  A publication of a workshop held in Naples that provided an opportunity for researchers to discuss the best available science on the natural history of Mediterranean red coral, as well as how it is managed throughout the region and utilized around the world.

The Nature of the Pigments in Corals and Pearls: A Contribution from Raman Spectroscopy, L. Bergamonti, D. Bersani, G. Csermely, and P.P. Lottici, Spectroscopy Letters, Vol. 44, No. 7/8, pp. 453-458, (2011).  The authors report the results of a spectroscopy study of coloring pigments in corals and pearls.

Detrimental Effects of Ocean Acidification on the economically important Mediterranean Red Coral (Corallium Rubrum), L. Bramanti, J. Movilla, M. Guron, E. Calvo, A. Gori, C. Dominguez-Carrió, J. Grinyó, A. Lopez-Sanz, A. Martinez-Quintara, C. Pelejero, P. Ziveri, and S. Rossi, Global Change Biology, Vol. 19, No. 6, pp. 1897-1908, (2013).  Evidence is presented that the mean predicted decrease in ocean acidity (0.3-0.4 pH units) by the end of the century will have detrimental effect on red coral populations.

Über die Färbung dere Korallenskelette [About the Coloring of the Coral Skeleton], F. Schmitz, Gemmologie – Zeitschrift der Deutschen Gemmologischen Gesellschaft, Vol. 62, No. 3/4, pp. 73-84, (2013).  A review is given of the causes of color in corals.

Deep-Water Red Coral from the Island of Sardinia (North-West Mediterranean): A Local Example of Sustainable Management, M.C. Follesa, R. Cannas, A. Cau, C. Pedoni, P. Pesci, and A. Cau, Marine and Freshwater Research, Vol. 64, No. 8, pp. 706-715, (2013).  Since 1979 the fishing of red coral in the waters around Sardinia has been regulated by regional laws designed to prevent overharvesting.  This study demonstrates how these fishing regulations have resulted in better management of this importance marine resource.

Micro-Raman Investigation of Pigments and Carbonate Phases in Corals and Molluscan Shells, L. Bergamonti, D. Bersani, S. Mantovani, and P.P. Lottici, European Journal of Mineralogy, Vol. 25, No. 5, pp. 845-853, (2013).  The authors present results of a study of coloring pigments in certain corals and shells.

The Red Coral Populations of the Gulfs of Naples and Salerno: Human impact and Deep Mass Mortalities, G. Bavestrello, M. Bo, S. Canese, R. Sandulli, and R. Cattaneo-Vietti, Italian Journal of Zoology, Vol. 81, No. 4, pp. 552-563, (2014).  The use of remotely operated vehicles from a research vessel allowed the authors to survey coral colonies along the western coast of Italy to assess the stage of population health.

Gem News: Dyed Bone as a Red Coral Imitation, G. Choudhary, Gems & Gemology, Vol. 50, No. 2, pp. 164-166, (2014).  The author describes a coral imitation material and how it can be gemologically identified.

Identification of the Chromophores in Corallium Rubrum Gem-Quality Corals by HPLC/UV, ESI-MS, and 1H NMR Spectroscopy, S. Bracco, P. Fumagalli, P. Fusi, C. Santambrogio, V. Rolandi, and A. Brajkovic, Periodico di Mineralogia, Vol. 85, No. 1, pp. 83-93, (2016).  Corals are calcitic biomaterials derived from branched skeletons of Cnidaria marine invertebrates.  This study suggests that the colouring pigment profile of red corals is more complex than previously thought.  Data collected by the authors indicate the presence of two carotenoids and well as traces of other pigments.

Distribution and Population Structure of Deep-Dwelling Red Coral in the Northwest Mediterranean, M. Angiolillo, A. Gori, S. Canese, M. Bo, C. Priori, G. Bavestrello, E. Salvati, F. Erra, M. Greenacre, and G. Santangelo, Marine Ecology, Vol. 37, No. 2, pp. 294-310, (2016).  The authors present results of a study in three areas of the Tyrrhenian Sea that have been historically exploited for coral production.

Modeling Red Coral (Corallium Rubrum) and African Snail (Helixia Aspersa) Shell Pigments: Raman Spectroscopy versus DFT Studies, T. Kupka, A. Buczek, M.A. Broda, R. Szostak, H.M. Lin, L.W. Fan, R. Wrzalik, and L. Stobiński, Journal of Raman Spectroscopy, Vol. 47, No. 8, pp. 908-916, (2016).  The organic pigments in red coral are present in an inorganic matrix that consists of block of calcite.  From their results, the authors suggest possible pigments for coral coloration.

Raman Investigations to Identify Corallium Rubrum in Iron Age Jewelry and Ornaments, S. Fürst, K. Müller, L. Gianni, C. Paris, L. Bellot-Gurlet, C.F.E. Pare, and I. Reiche, Minerals, Vol. 6, Article 56, pp. 1-23, (2016). The study of coral artifacts is important to investigate questions such as ancient trade patterns and economic structures.  However, this material tends to lose its intense red color and shiny surface due to ageing processes associated with archaeological conditions, thus making them more difficult to distinguish from other light colored materials. The authors present a non-destructive multi-stage approach to identify archaeological corals from other materials in Iron Age jewelry and ornaments.

Precious Coral Non-Destructive Characterization by Raman and XRF Spectroscopy, M. Macchia, V. Resta, G. Quarta and L. Calcagnile, X-ray Spectrometry, Vol. 45, No. 5, pp. 281-287, (2016).  This study was conducted to provide additional means of distinguishing corals from the Mediterranean Sea and the Pacific Ocean.

Specific Cases of Coral Treatments – Identification and Correct Terminology, F. Sequino. Rivista Italiana Di Gemmologia, Vol. 1, No. 2, pp. 47-56, (2017).  A review is presented of coral treatments and treatment detection.

A Connection to Coral, M. Campbell-Pedersen, Gems & Jewellery, Vol. 26, No. 3, pp. 24-26, (2017). A general discussion of precious corals and legal protections to prevent their commercial exploitation.

Differential Response to Thermal Stress of Shallow and Deep Dwelling Colonies of Mediterranean Red Coral Corallium rubrum (L., 1758), A. Cau, L. Bramanti, R. Cannas, D. Moccia, B.M. Padedda, C. Porcu, F. Sacco, M.C. Follesa, Advances in Oceanography and Limnology, Vol. 9, No. 1, pp. 13-18, (2018).  The authors present results of a study of seawater temperatures on red coral populations from all the coast of Sardinia.