A fixed star indicating manufactured asterism helps to identify an imitation star sapphire.

Recently, a 23.67 ct pear cabochon aquamarine with light greenish blue color and poor clarity was sent to the Taiwan Union Lab of Gem Research (TULAB) for identification.

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.

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.

Careful comparison of two GIA reports reveals a fraudulent inscription on a laboratory-produced diamond presented as a natural.

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.

Accidental laser damage likely caused unusual internal spiral markings in a 2.44 ct CVD-grown diamond.

The Carlsbad laboratory recently had the chance to examine a 4.60 ct cushion-cut zircon with truly unusual color behavior.

Creative faceting highlights an octahedral-shaped cloud inclusion in a 2.01 ct diamond octahedron.

A group of large, high-quality CVD material demonstrates the continued challenge of identifying laboratory-grown gems.

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

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.

The Tokyo lab examined a stunning double cat’s-eye emerald whose chatoyancy was created both by its cut and its inclusions.

A colorless topaz from Nigeria hosts the only known example of willemite as an inclusion in topaz.

加利福尼亚州卡尔斯巴德 – 2021 年 11 月 9 日 – GIA团体 - 全球有 3,300 多名从业员和数十万毕业生—向本周初去世的行业代表人物Helene Fortunoff 的家人表示哀悼。

CARLSBAD, Calif. – Sept. 13, 2021 – In mid-August, as reported in the media, police in Surat, India, uncovered a fraudulent scheme involving counterfeit inscriptions linking lower-quality diamonds to GIA diamond grading reports for higher-quality stones.

Using customized, image-based measurement systems to quantify the effect of fluorescence on the color, brightness, and transparency of gem diamonds viewed in both face-up and table-down orientations.

An overview of the Summer 2021 Gems & Gemology content.

Documents Namak Mandi’s transformation from a salt market to one of Pakistan’s primary gem trading centers, with a look at the commercial activities taking place today.