Commercial quantities of gem-quality chrysoprase and green prase opal (nickel-bearing chalcedony and common opal, respectively) have been recovered from altered serpentinite deposits near Haneti, ...

Commercial quantities of gem-quality benitoite are known from a single location in the world, the Benitoite Gem mine in the New Idria district of San Benito County, California. A barium titanium ...

The GIA Laboratory-Grown Diamond Report includes full quality assessment with a plotted clarity diagram. Color and clarity specification are described on the same scale as the GIA Diamond Grading ...

Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value. (The exception to this is fancy color diamonds, ...

Although various forms of paints and coatings intended to alter the color of diamond have likely been in use for almost as long as diamonds have been valued as gems, the modern era of diamond ...

The locality origin of natural-color blue sapphires from Kashmir can, in many cases, be positively identified. However, the field of origin determination is a very complex one – especially with the ...

The GIA Cultured Pearl Classification Report is an abbreviated report that provides classification information on unmodified cultured pearls. This dossier-sized report includes a detailed ...

Birthstones are a fun, popular and colorful introduction to the world of gemstones. They appeal to audiences around the world regardless of gender, age, nationality or religion. Birthstones carry ...

A new production of hydrothermal synthetic emeralds, grown in the Czech Republic with Italian technology, has been marketed since December 2004 with the trade name Malossi synthetic emerald. Several ...

A color-change sapphire was recently submitted to the GIA lab in Carlsbad for an origin determination report. The 5.68 ct transparent cushion mixed cut displayed a strong color change from grayish ...

As a result of changes in the manufacturing process, recent production of the synthetic fire opal marketed as “Mexifire” exhibits some new properties. While the earlier material could be identified on ...

GIA 与北大资源研修学院 (Peking University Resource College) 开展合作办学项目，在深圳提供校园课程、实习班和学生工作室。这些课程由 GIA 老师用中文授课。 除非另有说明，所有课程均用中文授课。