Lapis Lazuli
LAPIS or LAZURITE is a rare and prized mineral; used in both jewelry and carvings. It was first mined thousands of years ago in northeastern Afganistan, where the richest lapis still is found today.
Lapis occurs mostly as lapis lazuli, a mixture of lazurite and lesser amounts of pyrite and white calcite. The color of the highest quality material is a rich, deep blue, with no calcite visible. Lower grades (today often called "denim lapis"), have more of a spotty look, with patches of lazurite in a matrix of calcite.
The stone has a medium hardness, and prices vary in today's market from $20/lb. for low-grade rough material up to several hundred dollars per pound for the very highest quality. Lapis is also mined in Chile, Siberia, and is found in minor amounts in many countries, including the U.S.
LAZULITE is a different mineral, chemically as well as in its occurence, but also is bluish in color. It is distinguished from lapis by the absence of pyrite as well as calcite.
Chemistry: Sodium calcium aluminum silicate sulfur sulfate ♦ Class: Silicates ♦ Subclass: Tectosilicates ♦ Group: Both the Sodalite and feldspathoid groups ♦ Associated Minerals: Calcite, pyroxenes and pyrite ♦ Crystal system: Isometric ♦ Moh's hardness: 5-5.5 ♦ Transparency: translucent to opaque ♦ Luster: dull to greasy ♦ Color: brilliant blue with violet or greenish tints ♦ Cleavage: Poor ♦ Fracture: Uneven ♦ Localities: Afghanistan; Chile; Russia; Italy; USA - California (San Bernardino Mountains and Ontario Peak) and Colorado (Sawatch Mountains).