During the past 25 years, the corundum market has been transformed from one of medium to high-priced gems to one that encompasses nearly all price ranges. This transformation was caused by the ...

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 ...

The separation of naturally colored lavender jadeite from color-treated material is a problem that has long plagued gemologists. One theory is that the dyeing agents being used are of an organic ...

GIA Instruments works hand-in-hand with GIA’s laboratory, education and research teams, as well as the jewelry trade to develop the instrumentation you need to prepare you for the challenges of ...

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, ...

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 ...

10月生まれの方は、誕生日を祝福するのに2つの素晴らしい誕生石、オパールとトルマリンをお楽しみいただけます。10月の誕生石は、両方とも無限の色の組み合わせを持ち、美しい色を生み出すことを特徴とします。これら2つの10月の誕生石について詳しく ...

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, ...

Pink-to-red coral has a long history as an ornamental gem material in jewelry, carvings, and sculptures. However, due to a variety of environmental and legal factors, the supply of high-quality, ...

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 ...

Adjacent amethyst and citrine colors in the same crystal of quartz have been reported from South America, although there appears to be uncertainty as to the exact locality of origin. Such material has ...

The best ametrines show distinct areas of orangy yellow and purple. These colors are featured in this graceful cut design. Photo by Lydia Dyer, © John Dyer & Co ...