Editorial Gems & Gemology, Summer 2018, Vol. 54, No. 4

Pink Diamonds, Russia’s Amber Room, and More…

Duncan Pay

The beauty and desirability of pink diamonds is exemplified by the Winston Pink Legacy, a stunning 18.96 ct Fancy Vivid pink diamond that realized US$50 million at auction in November 2018. Such sought-after diamonds are the subject of the third installment of our colored diamonds series. GIA researchers Sally Eaton-Magaña, Troy Ardon, Karen Smit, Christopher Breeding, and James Shigley summarize the current science on natural-color pink to red diamonds and detail the cause of their color. The authors provide an unprecedented gemological and spectroscopic characterization by presenting absorption and luminescence spectra drawn from a representative sample of 1,000 diamonds from GIA’s database.

“An unprecedented characterization of naturally colored pink to red diamonds…”

Our second paper, by GIA’s Russell Shor, surveys the history of the legendary Amber Room. Originally commissioned for Prussia’s King Frederick I in the early 1700s and presented to Czar Peter I of Russia in 1716, the amber panels disappeared from St. Petersburg during the Second World War. In 1979, the Soviet Union initiated a painstaking reconstruction of this cultural treasure. Besides its rich history, the author provides firsthand accounts from those who participated in its recreation.

Next, Che Shen, a graduate student at the Gemmological Institute of China University of Geosciences in Wuhan, and Ren Lu investigate the color origin of gem-grade diaspore using LA-ICP-MS spectrometry.

A reaction rim or “corona” results from alteration of a crystal’s exterior after its formation due to changes in geological conditions. In our fourth paper, researchers led by Nguyen Ngoc Khoi, from the Hanoi University of Science, provide a study on corundum with spinel corona from northern Vietnam. The authors explain the genesis of the corona by examining its reaction textures, chemical composition, and mineral inclusions and applying thermodynamic phase equilibria calculations.

Our fifth paper offers a gemological characterization of pipi pearls from the bivalve mollusk Pinctada maculata. Authors Nanthaporn Nilpetploy, Kwanreun Lawanwong, and Promlikit Kessrapong detail the internal structures and further investigate these small, sometimes strongly colored natural pearls using microradiography and UV-Vis, Raman, and photoluminescence spectroscopy.

Our final article is a brief summary of diamond inclusions by GIA’s Nathan Renfro, John Koivula, Jonathan Muyal, Shane McClure, Kevin Schumacher, and James Shigley. A foldout wall chart with photomicrographs showcasing remarkable inclusions in natural, synthetic, and treated diamonds accompanies this article.

Besides our six articles and the chart, there’s plenty to enjoy in our regular features: Lab Notes offers analysis of three freshwater blister pearls attached to their host shells, De Beers’ Lightbox CVD-grown diamonds, and an exceptionally rare Montana ruby. Our new Diamonds from the Deep section provides an examination of how diamonds form in the deep earth. Micro-World serves up an array of internal features observed in gem materials, while Gem News International reports on sapphire treated with high pressure and high temperature, coated rough and faceted synthetic moissanite, and gemological conferences around the world.

Finally, don’t forget to check our listing of the 2018 G&G Challenge winners, and please do remember to cast your vote for the Most Valuable Article of 2018.