The De Beers Cullinan Blue was the early buzz of the spring 2022 auction season, with the 15.10 ct Fancy Vivid blue step-cut diamond far surpassing Sotheby’s presale estimate of $48 million. Bringing ...

Established in 1931, the Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, colored stones, and pearls. A public benefit, nonprofit institute, GIA is the leading ...

The authors used Vis-NIR spectral measurements combined with LA-ICP-MS data to investigate the usefulness of absorption spectra for differentiating between copper and iron as sources of greenish blue ...

Diamonds have a long history as a premier gemstone—a natural consequence of their beauty, rarity, and superlative physical properties such as extreme hardness. Diamonds that are mined for use as ...

The Karowe Diamond Mine in Botswana, owned and operated by Lucara Diamond Corp., has gained international recognition for producing large, high-quality type IaB or coexistence of IaB with IIa diamonds ...

Diamonds are the most amazing of gems. Just as amazing, however, is how natural diamonds reach Earth’s surface. Diamonds are formed 150 to 700 km deep in Earth, and are then carried upward in a rare ...

In November 2022, a parcel of 24 approximately 0.5–1.2 ct spinel crystals, described as cobalt-diffused, were obtained directly from a treater by the research team at GIA in Bangkok. Of these, seven ...

Figure 1. Glass in a silver brooch, hallmark from 1866. Private collection, photo by Jaroslav Hyršl. Tectites are members of a large group of impact glasses, formed by the collision of a meteorite on ...

Gem inclusions are mineral crystals or cavities filled with fluid and/or gas that occur in a host gemstone. Many gems contain microscopic inclusions (ranging in size from >1 mm down to submicroscopic ...

The Imperial Flame, a superb natural color Brazilian topaz, was fashioned from a 615 ct crystal recovered over 20 years ago. The finished piece measures 89.53 × 20.56 × 19.15 mm and weighs 332.24 ct.

Sapphire, rough and faceted, from the Rock Creek deposit in Montana has become one of the pillar gems of American origin in the global colored gemstone market. Over the past 10 years, Potentate Mining ...

Two specimens of faceted crystalized carbon - both are crystal clear and give off a kaleidoscope of spectral colors in direct light. They appear to be identical. One, however, is a billion or more ...