Lapis lazuli, often referred to as just 'lapis', has been used as a gemstone for thousands of years. It has been mined from Afghanistan since the early 7th millennium BC.
Although the colour of lapis lazuli is defined by its name, 'the blue stone', its colors can actually range from slightly greenish blue to violetish, medium to dark and from low to highly saturated. The blue is owed to sulfur coloring agents. The finest stones exhibit an evenly distributed color and have no visible deposits of calcite, although a moderate amount of gold pyrite flecks is considered acceptable. Too much pyrite can result in a dull, greenish tint, while calcite can predominate the mix, giving the stone an overall less appealing lighter blue shade.
Lapis lazuli comes in various shapes and cuts. It is mostly cut en cabochon for rings, beads, bracelets and necklaces, as well as carved sculptures, vases and various ornamental objects. Round, spherical and oval shapes are most popular, followed by fancier hearts and trillions.