Here's a piece of lapis lazuli that came in to our house a few days ago. This beautiful piece came from Afghanistan.
According to Wikipedia:
Lapis lazuli is one of the stones with the longest tradition of being considered a gem, with a history stretching back to 5000 BC. ... Lapis is a rock and not a mineral because it is made up from various other minerals. The main component of lapis lazuli is lazurite (25 to 40 percent), a feldspathoid silicate mineral composed of sodium, silicon, oxygen, sulfur, and chlorine. Most lapis also contains calcite (white), sodalite (blue) and pyrite (yellow).
The rock is cubic; hardness: 5.5; S.G. 2.7 – 2.9; vitreous/greasy luster.