Whether you’re taking the next step in your professional journey or starting a new career, GIA courses and diploma programs prepare you for success. We offer the finest gem and jewelry education in ...

この75.47カラットのHooker（フッカー）エメラルドは、オスマン帝国最後のスルタンであったアブドゥル·ハミド2世が着用したもの。 - Chip Clark、提供：Smithsonian Institution, National Museum of Natural ...

For the first time ever, the famous Hope diamond was graded by a widely recognized system. Although the 45.52-ct weight was confirmed, the GIA Gem Trade Laboratory graders found the clarity—recently ...

Designed for clients who seek in-depth insights into every aspect of a jewelry item. Comprehensive analysis of the diamonds in an item, including number of stones, shape, estimated carat weight, color ...

Many unusually large South Sea cultured pearls have been identified at GIA laboratories in the past (e.g., Fall 2013 Lab Notes, pp. 172–173; Summer 2023 Lab Notes, pp. 216–217). However, a recent ...

At the AGTA show, the author spoke with Brent Smith, owner of Phoenix Gems (Holly, Michigan), who shared a few parcels of rough spinel of different colors recently mined in Malawi. According to Smith, ...

Diamond color is usually the result of selective absorption of incident white light. The unabsorbed portion of this light is transmitted through the diamond and is interpreted by the human vision ...

Figure 1. Left: 18K yellow gold “Flames” ring with 25.19 ct Mexican fire opal. Right: This 18K yellow gold “Spice” ring ...

A 1.09 ct D-color diamond grown by chemical vapor deposition (CVD) was recently submitted to the Mumbai laboratory. This submission displayed an interesting blue band, seen through the pavilion facets ...

Chemical vapor deposition (CVD) technology has been widely used to grow diamonds for the jewelry market, targeting popular colors and sizes. The majority of these products are colorless to ...

A look at the history of analytical instruments used for gem testing. UV-Vis-NIR spectroscopy measures how gemstones absorb and interact with light across the ultraviolet, visible, and near-infrared ...

The published literature offers only a few records of direct measurement of the natural radioactivity in nephrite. The present study used high-purity germanium (HPGe) low-background gamma-ray ...