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Learn about spinel's durability and how to care for your spinel jewelry.

Individual opals are as diverse as snowflakes or fingerprints and can vary widely in appearance and quality. Learn about the factors that make opals so desirable!

Not all feldspars that bear the name “sunstone” are from the same side of the feldspar family—both the orthoclase and the plagioclase species boast a sunstone feldspar variety. The name sunstone refers to the gem’s appearance rather than to its chemical makeup.

In the early 1800s sunstone was a little-known, rare, and costly gemstone. It wasn’t until finds in Norway, Siberia, and other parts of the world that sunstone became somewhat more widely recognized, more available, and less expensive.

Learn about peridot's durability and how to care for your peridot jewelry.

Peridot is the gem variety of the mineral olivine. Its chemical composition includes iron and magnesium, and iron is the cause of its attractive yellowish green colors.

Learn about pearl's durability and how to care for your pearl jewelry.

Learn about the factors that make sunstone so desirable.

ジェダイトとオンファサイトとの区別の調査に加え、これらの石の定義に関する現在のGIAのポリシー。

モザンビーク北部産とされる魅力的な新しいルビーがタイの宝石市場に登場し始めています。 この石はタンザニア・ウィンザ産のルビーに似ていますが、本研究は顕微鏡検査によって鑑別できることを示しています。

A distinguished educator who taught GIA’s first overseas courses, he later served as Institute president and Governor for Life.