====== Sapphire ======
A **Sapphire** is a precious stone.

This gem of hardness 9 (after [[Mohs]]) comes in shades of blue, green and yellow or colorless. The colorless variant, very rarely also the blue, was sometimes used as bearing stone ([[jewel]]) and [[capstone]] in high quality [[Pocket watch|pocket]] and [[wristwatch]]es.

With high quality watches, it is now generally common that the watch glasses are made of synthetic [[sapphire crystal]].


{{tag>Terms Watch_materials}}