Established in 1931, the Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, colored stones, and pearls. A public benefit, nonprofit institute, GIA is the leading ...

The 75.47-carat Hooker Emerald was worn by Ottoman Sultan Abdul Hamid II, the last sultan of the Ottoman Empire. Photo by Chip Clark, courtesy Smithsonian Institution, National Museum of Natural ...

Everywhere on earth, people honor and appreciate the beauty and mystery of gems. And so it follows that everywhere you go, you also find the gem and jewelry industry. Just like the gems that are at ...

Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA.

To address concerns about laboratory-grown and treated diamonds being mixed into parcels of melee, GIA has developed an automated system to analyze and sort melee-size diamonds quickly and accurately.

Opal can range from 5 to 6.5 on the Mohs hardness scale. Hardness and toughness Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with ...

标记每个晶体边缘的切口被称为重入角。 有色宝石专家根据宝石所显示的颜色变化程度以及它们在不同的光线条件下所显示的红色和绿色色彩品质，来评定优良亚历山大变石。 寻找珠宝商 使用邮政编码寻找您附近有 GIA 报告和有 GIA 训练有素的工作人员的珠宝商 。

処理に関連する耐久性の問題がない場合、ルビーは非常に耐久性の高い宝石である。 - 提供：Jan Goodman Co. 硬度と靭性（じんせい） 宝石や鉱物の硬度はモース硬度スケールで測定されます。 モース硬度の数字はある1つの鉱物が他の鉱物によって傷つけられる ...

GIA instructors are passionate educators who bring years of industry experience to the classroom. All are leaders in their fields, and all are dedicated to helping you gain knowledge, acquire skills ...

如果您出生于六月，那么您很幸运，可以拥有三种生日石。六月是仅有的三个有三种生日石的月份之一（另外两个月份是八月和十二月），让您有各种各样美丽的生日石可以选择。 六月生日石是珍珠、亚历山大变石和月光石。有这么多吸引人的选择，六月生日的 ...

Due to the overwhelming popularity of GIA’s limited time, no-charge offer, all GIA Essentials classes starting in May and June – the period of the offer – are full. The offer is closed and we cannot ...

Blue sapphires are currently being mined on an exploratory basis from alluvial deposits at the Lindi mine, near the town of Mingxi in Fujian Province. The geology and occurrence of the sapphires ...