Often referred to as just "lapis", this gemstone has been used for thousands of years and mined from Afghanistan since the early 7th millennium BC. This makes it one of the most ancient gems known and it has been used by people from Caucasians to the Mehrgarh and the Mauritanians. The funeral mask for the ancient Egyptian pharaoh ‘King Tut’ was discovered to have been decorated with lapis.
Formed in crystalline marble through the geological process of contact metamorphism, lapis lazuli is a gem that is technically defined as a rock and not as a mineral. Its structure is composed of lazurite and the remaining parts are a mix of sodalite, calcite, pyrite and other minor constituents. All of these ingredients influence its exact coloring.
Afghanistan is known to produce the finest quality lapis lazuli and is the most significant source. However, it is also mined in Russia, the US, Canada, Chile, Argentina, Angole, Italy, India, Myanmar and Pakistan.
The color can vary from greenish blue to somewhat violet, medium to dark and from low to highly saturated. The blue, however, is attributed to sulfur which is the main coloring agent.
The most prized color of is the slightly violet-blue shade. Stones are also referred to as "Afghan" or "Persian" and often described using specific localities.
Lapis lazuli occurs opaque in terms of its clarity and can have a vitreous to greasy and sometimes a dull luster.