CARLSBAD, Calif. – November 4, 2024 – The GIA laboratory in Ramat Gan, Israel, will end operations by the end of 2024 due to changes in the global diamond industry that resulted in significant ...

Figure 1. This cross section through ancient thickened continental lithosphere and underlying mantle shows the two major depth intervals of diamond formation. The majority of mined diamonds originate ...

On January 24th 2024, Wim Vertriest, GIA Manager of Field Gemology, gave GIA’s first student lecture of the year at the GIA World Headquarters in Carlsbad, California. In this lecture, Wim explored ...

A well-known collector mineral, wavellite (Al 3 (PO 4) 2 (OH) 3 •5H 2 O), is named after its discoverer, British surgeon Dr. William Wavell. Wavellite mineral specimens seen on the market often occur ...

The perceived color of light after passing through a polished wafer of any uniaxial material can be calculated using transmittance spectra (both polarized and unpolarized) and the incident light angle ...

Carved single-crystal diamond rings are rare, with few examples to reference (see Spring 2020 Lab Notes, pp. 132–133). But with advancing technology in the laboratory-grown diamond industry, the ...

Under a conventional gemological microscope, all of the pearls appeared to have even color distribution. Minor color concentration spots were found on the surface of five samples (FW02, FW07, FW08, ...

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 ...

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 ...

A natural 5.20 ct type Ia SI 2 Fancy Dark yellowish brown diamond with natural anhedral crystal inclusions was submitted to the New York laboratory for grading services and returned. After being ...

GIAについて 1931年設立の独立非営利組織であるGIA（Gemological Institute of America）は、宝石学における世界有数の権威として認められています。GIAはカラー、クラリティ、カット、カラット ウェイトからなる有名な4Cを考案し、さらに1953年にはダイヤモンドの品質の基準として世界中で認知されて ...

Of the variety of inclusions that can be seen in spinel, perhaps the most familiar are angular octahedral crystals. In many cases, we even see these crystals arranged in neat rows, forming delicate ...