Both asterism and chatoyancy are observed in a color-change sapphire.

Large near colorless, blue, and yellow diamonds broke auction records at Christie’s and Sotheby’s in the first half of 2022.

Pinkish orange crystal inclusions in a faceted quartz are identified as the rare phosphate mineral triplite.

Microscopic observation unveils the first known instance of skeletal metallic inclusions in Brazilian Paraíba tourmaline.

The Nineteenth Annual Sinkankas symposium, held at GIA’s Carlsbad, California campus, focused on gems and minerals of San Diego County.

Fiber-optic light creates a night sky scene in a yellow sapphire from Madagascar.

An exceptionally large South Sea bead cultured pearl is examined at GIA’s Mumbai laboratory.

GIA president and CEO Susan Jacques receives the American Gem Society’s highest honor.

An intriguing metallic inclusion is observed in a faceted garnet.

A newly developed treatment creates a phantom structure in opal visually similar to natural phantom opal.

A look at a 34.59 ct CVD-grown diamond examined at GIA’s Hong Kong laboratory.

An iridescent feather inclusion in natural diamond bears resemblance to Rainbow Mountain in Peru.

Unusual natural pink diamonds displaying faint yellow color zoning and strong yellow fluorescence are studied in the Carlsbad laboratory.

Isolated nitrogen confined to the outer surface of a 0.98 ct diamond causes “yellow skin.”

A feather inclusion with iridescence caused by thin-film interference in diamond resembles an insect wing.

A look at a very rare instance of a six-rayed star in aquamarine.

Various inclusions are observed in a batch of aquamarine samples from Xinjiang, China.

Offers a comprehensive look at a variety of augite from Dong Nai, Vietnam, detailing its formation and gemological characteristics.

Reports on a newly discovered treatment process for producing a deep blue color in natural spinel and proposes identification criteria.

Investigates the mineral and chemical compositions and surface morphology characteristics of brown mammoth ivory to identify the origins of its brown color.