Chemical Formula The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)8Al6Si6O24(S,SO)4
Color Blue, Multicolored
Hardness 5 – 5.5
Crystal System Isometric
Refractive Index 1.5
SG 2.4 – 2.5
Double Refraction None
Luster Vitreous to greasy
Mineral Class Rock that is mostly Lazurite with minor , Pyrite, and other minerals
Lapis Lazuli is often called Lapis for short. In fact, the shorthand name “Lapis” is actually used more often to describe this gemstone than the full term “Lapis Lazuli”. Lapis Lazuli is rarely without any of the white Calcite present. Embedded Pyrite crystals within most Lapis Lazuli add to the sparkle and naturalness of this gemstone, and when evenly distributed in small amounts makes it more desirable. A deeper blue color makes this gemstone more valuable, as well as a minimal amount of spotting or streaks of white Calcite.
Lapis Lazuli is a sensitive gemstone, and can be chipped or cracked easily when banged. It is also relatively soft so care should be exercised to prevent it from getting scratched. It is also slightly porous and should be protected from chemicals and cleaning solvents.
Lapis Lazuli, being an opaque gemstone, is cut into cabochons and beads, and used mainly in bracelets, necklaces, and pendants. Ornate carvings and utensils are also carved out of Lapis, especially animal carvings, snuff boxes, and talismans.
LazuriteSwiss Lapis – Jasper that is dyed blue to simulate Lapis Lazuli. Gilson Lapis – Synthetic Lapis simulant that is used to simulate Lapis Lazuli.The color of Lapis Lazuli is natural, and it is generally not treated or enhanced, though occasionally lighter colored stones may be dyed a deeper blue.Lapis Lazuli SOURCESSIMILAR GEMSTONESLarimar is a blue variety of the mineral Pectolite. Pectolite is not a rare mineral and is found throughout the world, but the exquisite sea-blue color exhibited in the Larimar variety is very unique, and only comes from one place in the world. It is found only in a limited deposit in the Dominican Republic, and is virtually the only gemstone to be found in the entire Caribbean. Its lovely sea-blue color is very reminiscent of the Caribbean seas.
Azurite is lower hardness and usually has a darker tint. Sodalite may be difficult to distinguish, though it is usually lighter in color and more coarse-grained.
The most significant source of Lapis Lazuli is Afghanistan. Other commercial deposits are in Russia and Chile.
A synthetic simulant of Lapis Lazuli has been created using the Gilson process. Although Gilson Lapis may look similar to Lapis Lazuli, it not made of the same composition, and lacks the natural random patterns displayed in most true Lapis Lazuli. Howlite and Jasper may also be dyed an ultramarine blue to simulate Lapis Lazuli.
Lapis Lazuli TREATMENTS AND ENHANCEMENTS