Explore sapphire history, research, quality factors, and more in the GIA Gem Encyclopedia.

There are other green gems, like tourmaline and peridot, but emerald is the one that’s always associated with the lushest landscapes and the richest greens. Ireland is the Emerald Isle. Seattle, in ...

探索五月生日石 — 祖母绿的意义和历史及产地。

Emerald is 7.5 to 8 on the Mohs scale and has fair to good toughness, making it a stone that requires more care in wearing than ruby or sapphire. Even so, emeralds are beautiful stones for all types ...

Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive.

5月の誕生石であるエメラルドの意味、歴史、産地について詳しく学びましょう。

8月の誕生石であるスピネルの意味、歴史、産地について詳しく学びましょう。

Corundum is stable under normal wearing conditions, which means it’s resistant to the effects of heat, light, and common chemicals. Boric acid powder will etch the surface of even untreated stones.