Lapis Lazuli is a semi precious stone formed during the metamorphosis of chalk into marble. It has a cubic crystal system, and is in the mineral class of lattice silicate.
Lapis Lazuli has been prized since antiquity for its intense blue color, and has been mined since 7th Millennium BC from a number of mines in the area of Afghanistan where a lot of beads of this semi-precious stone have been found.
It was also very popular to ancient Egyptians and used in the funeral mask of King Tutankhamun.
At the end of the Middle Ages, it began to be exported to Europe, where it was ground into powder and made into ultramarine, the finest and most expensive of all blue pigments, which was used by some of the most important artists of the Renaissance and Baroque.
Lapis Lazuli is still a very highly prized gemstone nowadays and the birthstone of the month of September.