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.

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

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

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.

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

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.

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.

The Carlsbad lab recently encountered a 2.42 ct green diamond showing signs of radiation treatment by the use of radioactive salts.

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

CARLSBAD, Calif. – Dec. 2, 2021 – The joy diamonds bring to people’s lives and the confidence inspired by a diamond grading report from the experts at GIA are at the center of GIA’s first new global consumer marketing campaign in more than a decade.

CARLSBAD, Calif. – Dec. 2, 2021 – The joy diamonds bring to people’s lives and the confidence inspired by a diamond grading report from the experts at GIA are at the center of GIA’s first new global consumer marketing campaign in more than a decade.

CARLSBAD, Calif. – Nov. 17, 2021 – The GIA Board of Governors held their first in-person meeting in two years, Nov. 5 – 8, in Carlsbad, California.

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.

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

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.

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

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