Tubular three-phase inclusions are observed in a Colombian emerald.

An overview of the Winter 2023 Gems & Gemology content.

The quality and size of this 4.04 ct CVD-grown diamond ring demonstrate the advancing technology in laboratory-grown diamonds.

Trigons and tetragons observed in a chameleon diamond indicate both octahedral and cubic growth.

Investigates the various chromophores responsible for color in four types of yellow sapphire.

Details the colors and optical effects caused by metallic copper inclusions in this gem-quality feldspar.

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

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

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.

After a slow start, the spring 2023 auction season ends with multiple broken records.

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

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

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

Gemstones formed in metamorphic environments offer insights into the earth’s history and the evolution of tectonic activity that led to their formation.

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

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

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

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

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