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 ...

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 ...

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 ...

Le Ngoc Nang, Pham Minh Tien, Pham Minh, and Pham Trung Hieu Anorthoclase, (Na,K)AlSi 3 O 8, is an uncommon variety of alkali feldspar that is the potassium-rich variety of high albite, distinguished ...

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 ...

Natural-color pink diamonds are exceptional treasures. The lead article in this issue, based on GIA’s database of more than 90,000 diamonds in the pink, orangy pink, purple, red, and brown color ...

Laboratory-grown CVD rough diamond (left), laboratory-grown HPHT rough diamond (middle) and natural rough diamond (right) Two specimens of faceted crystalized carbon - both are crystal clear and give ...

Research News Observations on the Heat Treatment of Basalt-Related Blue Sapphires Wasura Soonthorntantikul, Charuwan Khowpong, Ungkhana Atikarnsakul, Sudarat Saeseaw, Supharart Sangsawong, Wim ...

How Do Lithospheric Diamonds Form? Lithospheric diamonds (box B) often contain detectable nitrogen, implying that they crystallize from carbon- and nitrogen-bearing (C-N-bearing) fluids. Through the ...

GIA has studied lab-grown or manmade diamonds extensively over the past 30 years, and we know a great deal about the methods used to produce them and how they can be recognized. While synthetic ...

Figure 1. A comparison of the Mohs hardness scale and the Knoop hardness scale, a micro-hardness test where a pyramidal diamond point is pressed into the polished surface of the sample with a known ...

The round brilliant is the most popular diamond cut. Because of its popularity, assessment of this cut has been the subject of considerable research. Courtesy of Harold & Erica Van Pelt. Ask anyone ...