GIA’s New York laboratory reports on a 15.10 ct (17.47 × 11.53 × 7.94 mm) Fancy Vivid blue cut-cornered rectangular step cut named the De Beers Cullinan Blue diamond.

Researchers examine six specimens of banded turquoise, obtained through long-term cooperation of local miners in Zhushan County.

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.

The first installment of this column discusses the formation of colored stones from the crust-mantle transition and below.

Remarkable “horsetail” inclusions discovered in a demantoid garnet, while their origin and composition remain under discussion.

The Tokyo lab recently identified a unique localized distribution of cloud-like inclusions in a chrysoberyl.

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.

Unique diamond- and emerald-lensed spectacles from the Mughal Empire were tested in GIA’s New York laboratory.

The Carlsbad lab received a rhodochrosite cabochon featuring rhomboid-shaped fluid inclusions, causing a four-rayed star.

Contributes to the mining history of Austria’s Habachtal region, which is believed to be one of the earliest emerald deposits.

GIA’s New York laboratory reports a new record size for CVD laboratory-grown diamond.

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

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

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

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

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.

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 study on heat with pressure treatment of blue sapphires reveals FTIR patterns associated with different iron concentrations.