Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions
Karen V. Smit, Elina Myagkaya, Stephanie Persaud, and Wuyi Wang, August 6, 2018
Characterises a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.
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Gemmological Characterisation of Sapphires from Yogo Gulch, Montana
Nathan D. Renfro, Aaron C. Palke, and Richard B. Berg, August 6, 2018
A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.
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Inclusions in Natural, Synthetic and Treated Ruby
Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley, January 26, 2018
Provides a visual guide to the internal features of natural, synthetic and treated rubies.
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Saltwater Pearls from the Pre- to Early Columbian Era: A Gemmological and Radiocarbon Dating Study
Chunhui Zhou, Gregory Hodgins, Todd Lange, Kazuko Saruwatari, Nicholas Sturman, Lore Kiefert, and Klaus Schollenbruch, November 8, 2017
Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.
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The Very Deep Origin of the World’s Biggest Diamonds
Evan M. Smith, Steven B. Shirey, and Wuyi Wang, November 8, 2017
Explores an exceptional family of diamonds, referred to as “CLIPPIR” (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular and Resorbed), that formed in a super-deep environment.
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Synthetic Star Sapphires and Rubies Produced by Wiede’s Carbidwerk, Freyung, Germany
Karl Schmetzer, H. Albert Gilg, and Heinz-Jürgen Bernhardt, November 8, 2017
Details the process used by Wiede’s Carbidwerk to produce star synthetic corundum from the mid-1950s until the 1970s.
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Characteristics of Gem-Quality By-Product Synthetic Zincite
Ji Zhang, Yujie Gao, and Guanghai Shi, May 8, 2017
Investigates the properties of synthetic zincite produced by industrial kilns in Poland.
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A New Deposit of Gem-Quality Grandidierite in Madagascar
Delphine Bruyère, Claude Delor, Julien Raoul, Rufin Rakotondranaivo, Guillaume Wille, Nicolas Maubec, and Abdeltif Lahfid, November 7, 2016
Reviews the properties of exceptionally pure grandidierite from a new source.
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Amethyst from Boudi, Morocco
Fabrizio Troilo, Abdelghani El Harfi, Salahaddine Mouaddib, Erica Bittarello, and Emanuele Costa, April 30, 2015
An introduction to Moroccan amethyst, which features distinctive color zoning and inclusions.
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Three-Phase Inclusions in Emerald and Their Impact on Origin Determination
Sudarat Saeseaw, Vincent Pardieu, and Supharat Sangsawong, July 25, 2014
Discusses the role of three-phase inclusions in emerald, in combination with spectroscopy and trace-element analysis, in determining geographic origin.
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