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Figure 9. The parcel of rough spinel on the left, reportedly from Tajikistan, contains pieces weighing up to 48.5 g. The seven faceted spinels on the right (9.04–28.16 ct) were fashioned from some of this rough.

Purplish Pink Spinel from Tajikistan: Before and After Cutting

Nicholas Sturman, March 1, 2009

Purplish Pink Spinel from Tajikistan: Before and After Cutting

Suite containing over 36 carats of Yogo sapphire

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.

An Early Byzantine Engraved Almandine from the Garibpet Deposit, Telangana State, India: Evidence for Garnet Trade Along the Ancient Maritime Silk Road

H. Albert Gilg, Karl Schmetzer, and Ulrich Schüssler, August 6, 2018

Analyses the chemical composition and inclusion characteristics of this ancient artefact.

Gerd Dreher agate lily and Patrick Dreher citrine mouse

Gem Virtuosos: The Drehers and Their Extraordinary Carvings

Robert Weldon, Cathleen Jonathan, and Rose Tozer, January 26, 2018

A look at the artistic heritage of the Drehers, an influential family of gem carvers in Idar-Oberstein, Germany.

A blue synthetic star sapphire from past production of Wiede’s Carbidwerk

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.

Fabergé figures of Chamber Cossacks A.A. Kudinov and N.N. Pustynnikov

Fabergé Cossack Figures Created from Russian Gemstones

Timothy Adams and Christel Ludewig McCanless, August 3, 2016

Hardstone figures of two Russian imperial bodyguards, commissioned in 1912 by Nicholas II, demonstrate the House of Fabergé’s meticulous detail and craftsmanship.

Beryllium Diffusion of Ruby and Sapphire

John L. Emmett, et al., June 1, 2003

The heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade.

G. Robert Crowningshield: A Legendary Gemmologist

Thomas M. Moses and James E. Shigley, September 1, 2003

G. Robert (Bob) Crowningshield has made many significant contributions to the study of gems and the science of gemmology.

The 3543 CM-1 Infrared Absorption Band in Natural and Synthetic Amethyst and its Value in Identification

Vladimir S. Balitsky, Denis V. Balitsky, June 1, 2004

The proper use and limitations of IR spectroscopy for identifying natural versus synthetic amethyst of various types have been investigated, focusing on the region 3800–3000 cm-1.

A Gemological Pioneer: Dr. Edward J. Gübelin

Robert E. Kane, Edward W. Boehm, December 1, 2005

During a career that spanned more than 65 years, the eminent Swiss gemmologist Dr. Edward J. Gübelin (1913–2005) built a monumental legacy.

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