Learn about the factors that make lapis lazuli so desirable.

Learn about the factors that make sunstone so desirable.

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.

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.

The first woman on the executive team and head of GIA’s innovative marketing and public relations efforts for nearly 30 years.

Brendan Hoare specializes in mantle geochronology and geochemistry.

Evan M. Smith specializes in diamond geology.

Rachelle Turnier specializes in colored gemstone geochemistry

Bassoo specializes in Understanding the spatial distribution and geological causes of defects in green diamonds

Sona Tajiryan specializes in Early Modern History of Global Gem Trade.

Yang Mo specializes in Mathematics.

几千年来，红宝石和蓝宝石（通常为蓝色，有时也有各种其他颜色）一直都是最重要的有色宝石。这些刚玉族矿物包含各种颜色类别，历史上原产于东南亚和中亚地区，如今由于它们珍贵稀有、色彩瑰丽、坚硬耐磨，已经成为备受追捧的宝石。由于有向分布的矿物内含物，刚玉可以呈现出星光和猫睛光，在不同的光源下观察时，有时还会变色。

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