Lapis lazuli is an aggregate of three minerals in varying amounts: lazurite, calcite, and pyrite. It is also known simply as "lapis," has been used by people as a gemstone, sculpting material, and ornamental material for thousands of years. Lazurite grains provide its characteristic blue color. It has been mined from of Afghanistan since the early 7000 BC.

Lapis lazuli Deposits

Badakhshan Provinceof Afghanistan has been the traditional source of lapis lazuli. Other major sources are Chile and Lake Baikal in Siberia, Russia. Minor sources are Angola, Canada, Colorado (US), and Pakistan.

Lapis lazuli Hue

Its color ranges from deep violet blue and royal blue to light blue to turquoise blue to a greenish blue.The combination of different minerals in the aggregate determines the color. The most prized bright royal blue color is mainly derived from the presence of lazurite .Calcite appears as white flecks or streaks in the aggregate and Pyrite usually occurs as tiny, randomly spaced grains with a contrasting gold color. The lowest-quality lapis looks dull and green, the result of an excess of pyrite.

Lapis Lazuli Clarity and Surface

Lapis lazuli is opaque in clarity. The higher the percentage of lazurite grains in the aggregate, the darker the blue color. Lapis is often included with varying amounts of pyrite and its host rock matrix; calcite.It shows a waxy to vitreous luster.

Lapis Lazuli Cut and Shape

Lapis lazuli comes in various shapes and cuts. . Round, spherical and oval shapes are most popular, followed by fancier hearts and trillions. It is mostly cut into cabochon and beads for rings, bracelets and necklaces, as well as carved sculptures, and various ornamental objects.

Lapis Lazuli Treatment

Lapis lazuli is typically not treated or enhanced. It may sometimes be impregnated with wax or resin to improve color and luster. However, some lighter colored stones may be dyed into deeper blue which may also be coated or with wax or plastic to improve stability. 'Gilson lapis', the synthetic form of lapis and many simulations are available too.

Lapis lazuli care and cleaning

• Lapis has a Mohs hardness of about 5, which makes it quite soft for use in a ring, cuff links or bracelet if the stone is raised above the top of the setting or bezel.
• lapis can be damaged if the pieces are not isolated from one another ,therefore the jewelry should be kept in different compartments.
• Lapis can be quite sensitive to high temperatures, strong pressure, and harsh household chemicals. Use warm soapy water for cleaning.
• For dyed or impregnated stones, test a small area first to ensure stability.

Lapis lazuli gemological properties

Chemical Formula: [S,SO4,Cl2)2lAl6Si6O24] Sodium calcium aluminum silicate

Crystal Structure: (Cubic) rare, dense aggregates

Color: Lazur blue, violet, greenish-blue

Hardness: 5.00 to 6.00

Refractive Index: 1.50 (approximate)

Density: 2.50 to 3.00

Cleavage: Indistinct

Transparency: Opaque

Double Refraction: None

Luster: Vitreous, greasy to dull

Fluorescence: Strong: White, also orange, copper colored