Photochromic zircon shows significant color change from medium light greenish blue to very dark yellowish green.

A unique twinned crystal inclusion resembles a boomerang in a rough topaz.

An examination of 45 gems from the coronation crown of Napoleon III, using nondestructive mobile spectroscopic and gemological testing methods.

GIA’s New York laboratory reports on a 15.10 ct Fancy Vivid blue cut-cornered rectangular step cut named the De Beers Cullinan Blue diamond.

Rare optical phenomenon observed in four star quartz cabochons from Brazil.

GIA, the leader in gemological research, education and science-based gem identification and grading services, is expanding its gem origin services to provide retailers and consumers with the diamond source information they demand.

GIA welcomes Johanna Levy as the Institute’s first vice president of environmental, social and governance (ESG) programs.

GIA, the leader in gemological research, education and science-based gem identification and grading services, is expanding its gem origin services to provide retailers and consumers with the diamond source information they demand.

A 3.03 ct stone submitted to GIA’s Bangkok laboratory was identified as a ruby from Mozambique with no indication of heating.

A very light blue hexagonal apatite inclusion is observed in natural smoky quartz.

The New York laboratory reports on a new record size for CVD laboratory-grown diamond.

A maze-like pattern is observed in spinel from Vietnam.

The finale of a two-part series on the mining history of Austrian emerald deposits in the Habachtal region.

Four-billion-year-old meteorite carved into a life-sized human skull draws attention at the 2022 AGTA show.

Sellers and buyers alike were delighted to be back at Tucson for the show season after a two-year absence.

The author recently examined a 3.58 ct yellowish green yttrium aluminum garnet, a manufactured product known in the trade as “YAG,” that contained numerous large flux-filled fractures.

160 ct yellow sapphire rough from Sri Lanka.

A blue topaz recently examined by the authors contained an interesting and complex fluid-filled negative crystal that revealed some remarkable behavior when cooled down.

At the AGTA show, Rod and Nathaniel Cook of Washington Jade (Edmonds, Washington) told us about shifting their focus to cat’s-eye blue and bluish green nephrite jade.