Research Article Search Results

A newly found deposit of sapphire in Madagascar is explored.

Examination of a 0.40 ct near-colorless round brilliant diamond with a large inclusion resembling a dumbbell

A new opal deposit was discovered in 2008 near the village of Wegel Tena, in volcanic rocks of Ethiopia’s Wollo Province.

Northern Vietnam began producing significant quantities of rubies and fancy sapphires in the late 1980s.

Gem-quality rubies and pink to purple sapphires are being recovered from the Luc Yen and Quy Chau mining regions of Vietnam.

Geographic origin determination relies on a combination of gemological observations and advanced analytical tools. This contribution reviews the analytical methods commonly used to establish origin.

GIAは2008年以来、6大陸で90回以上の現地調査を実施し、22,000点を超えるカラーストーンの参照サンプルを収集してきました。産地が判明しているこの膨大なカラーストーンコレクションは、GIAの産地特定に関する研究を支えています。

The world ruby market has undergone dramatic change in recent years, especially with the development of ruby mining in Mozambique. This contribution outlines GIA’s methods and criteria for establishing the geographic origin of ruby.

In some cases, the value of a sapphire depends strongly on its geographic origin. This article details the origin data GIA has collected for blue sapphire and describes its methodology for using the data in geographic origin determination.

Reviews the mining history, market impact, and properties of ruby from northern Mozambique near Montepuez, now the world’s most productive source.

At the AGTA show, Rod Griffin (Rod Griffin Boulder Opals, Silverado, California, and Queensland, Australia) told us that the world market for all types of opals continues to be strong, but Australia’s opal industry is shrinking due to the costs, challenges, and changing regulations of mining.

Summarizes data collected by GIA on more than 90,000 natural diamonds in this color range and presents their gemological and spectroscopic properties.