Examines the mining and the internal, spectroscopic, and chemical features of peridot from this deposit, which possesses a rich olive green color and is available in large sizes.

One of the more subtle inclusion scenes gemologists sometimes observe in natural diamonds is the presence of crystallographically oriented structural defects known as “internal graining.”

A gemological analysis of blue Burmese sapphires from Mogok, based on a series of field expeditions over the last decade.

A reported new source of blue zircon in Malawi yields rough material for beautiful finished stones in the gem trade.

The Bangkok lab recently encountered a single round crystal of chondrodite in red spinel, a possible indicator of Burmese origin.

Analysis of a transparent yellow angular crystal inclusion in a Brazilian rock crystal quartz host suggests monazite.

Nacreous pearls are known to have platelet growth resembling fingerprints or topographic maps, but a less common appearance is nacre with a concentric spiral pattern.

An overview of the Winter 2021 Gems & Gemology content.

The Carlsbad lab recently encountered a 2.42 ct green diamond showing signs of radiation treatment by the use of radioactive salts.

加利福尼亚州卡尔斯巴德 – 12 月 16 日（星期四） – 作为宝石学研究、教育以及以科学为基础的宝石鉴定与分级服务领导者，GIA（美国宝石研究院）目前正在大力发展其卓越的服务体系和员工队伍，致力于向全球主要品牌和零售商提供创新产品。

加利福尼亚州卡尔斯巴德 – 2021 年 12 月 2 日 – 给人们的生活带来喜悦的钻石以及 GIA 的钻石分级专家报告所激发的信心是 GIA 十多年来首次全球消费者营销活动的核心。

加利福尼亚州卡尔斯巴德 – 2021 年 12 月 2 日 – 给人们的生活带来喜悦的钻石以及 GIA 的钻石分级专家报告所激发的信心是 GIA 十多年来首次全球消费者营销活动的核心。

CARLSBAD, Calif. – Nov. 17, 2021 – The GIA Board of Governors held their first in-person meeting in two years, Nov. 5 – 8, in Carlsbad, California.

Extensive analysis of early beads and pendants from archaeological sites in the French islands of the Lesser Antilles identified the objects as sudoite, which has never before been documented in any lapidary production.

A selection of 74 non-bead cultured and 12 bead cultured pearls grown in cultured pearl sacs and harvested directly from operated mollusks were collected and their internal structures examined using real-time microradiography and X-ray computed microtomography analyses.

Figure 1. The vivid colors seen in fine gem-quality spinel are derived from the mixing between multiple different chromophores in a range of ratios and concentrations, as in this fine 13.52 ct violetish purple spinel. Courtesy of the Dr. Edward J. Gübelin Collection. Photo by Robert Weldon/GIA.

Reports on the geology, background, and current state of mining and production at Iran’s largest turquoise mine.

Four pearls submitted to the Bangkok lab proved to be natural non-nacreous specimens dyed pink, apparently to imitate true conch pearls.

An overview of the Fall 2021 Gems & Gemology content.