Diamond Geology and Earth’s Formation in Winter Edition of Gems & #Gemology

Gems & Gemology Delves into Diamond Geology and Earth’s Formation

Winter 2013 issue reviews latest gemological research

Gems & Gemology Winter 2013 cover.
The cover image, of diamond crystal in kimberlite matrix,
was chosen to highlight the relevance of this gem material as part
of the Earth’s makeup. The combined weight of the piece,
retrieved from South Africa, is 314.47 carats.
This specimen is part of the Oppenheimer Student Collection
at the GIA Museum in Carlsbad. Photo by Robert Weldon; © GIA.

The Winter 2013 issue of GIA’s award-winning peer-reviewed quarterly journal Gems & Gemology (G&G) journeys to the Earth’s mantle to gain better insight into diamond geology; takes a look inside blue sapphires from the Baw Mar Mine in Mogok, Myanmar; provides an update on gem mining in Luc Yen, Vietnam; discusses the characteristics of coated jadeite jade; and much more. The issue is now available in print, and online with exclusive video content.

G&G’s cover story is by Dr. Steven B. Shirey, a noted isotope geochemist from the Carnegie Institution of Washington and a leader in the field of inclusion-dating techniques as applied to diamond, and Dr. James E. Shigley, GIA’s Distinguished Research Fellow. The piece examines two decades’ worth of research about natural diamond formation and how it corresponds to the Earth’s formation, and chronicles the current thinking of where, how, when and why natural diamonds form. Since it was proven that diamonds are up to billions of years older than their kimberlite or lamproite hosts, there have been significant advances in the analysis of diamonds and their mineral inclusions. These advancements have deepened understanding of diamond-forming fluids in the mantle, and in the relationship of diamonds to the deep geology of the continents and the convecting mantle.

Figure 28. Gem diamonds such as these, ranging in weight from 3.00 to 22.33 carats, result from unique geologic processes, adding to their desirability among today’s jewelry consumers.
Photo by Robert Weldon; © GIA.

Next is a report on the microscopic, chemical and spectroscopic features that differentiate the high-quality Baw Mar sapphire from classic gem-quality Burmese sapphire. In another feature, researchers explore the emergence of the Luc Yen area of Vietnam’s Yen Bai province as a producer of corundum, spinel, tourmaline and other colored stones. The issue also includes an analysis of 10 jadeite jade samples using DiamondView™ imaging, microscopy, spectroscopy and Raman spectrophotometry to determine the effects of coating.

2014 marks the 80th anniversary of Gems & Gemology. Since the first issue was published in 1934, G&G has been recognized as one of the leading academic journals in its field. In 2013, it was made available in its entirety online. Today, the award-winning quarterly journal is available both as a print subscription and at no cost on GIA’s website. 

About GIA

An independent nonprofit organization, GIA (Gemological Institute of America), established in 1931, is recognized as the world’s foremost authority in gemology. GIA invented the famous 4Cs of Color, Cut, Clarity and Carat Weight in the early 1950s and in 1953, created the International Diamond Grading System™ which, today, is recognized by virtually every professional jeweler in the world.

Through research, education, gemological laboratory services, and instrument development, the Institute is dedicated to ensuring the public trust in gems and jewelry by upholding the highest standards of integrity, academics, science, and professionalism. Visit www.gia.edu.