Lapis Lazuli
What is Lapis Lazuli?
Lapis Lazuli is a rare gemstone found in metamorphic rocks.
It is composed of lazurite with calcite, sodalite, and pyrite.
Lapis Lazuli is found in deep blue or purple colors.
It has been mined as early as the 7th millennium BCE in Sar-i Sang, Afghanistan.
It was even found at the site of the earliest known civilisation the Indus Valley Civilisation.
By the end of the middle ages Lapis had found its way to Europe and had been ground down and used as pigment for artists. Known as Ultramarine.
Lapis is the latin word for stone. And Lazuli comes from the Persian word lājevard which means sky or heaven.
In Persian folklore the stone is thought to be the whole starry sky shrunken down into a precious gemstone.
It is normally found in Afghanistan, Russia and Chile.
Colors and Types of Lapis Lazuli
There are many different types and colors of Lapis.
The colors can range from deep violet blue and royal blue to turquoise or greenish blue. Lapis is cut into inlays, cabochons or tablets, but it also makes beautiful beaded jewelry because of its matrix, which adds dimension and a natural quality.
| Chemical Classification | Inorganic - Rock (primarily composed of lazurite, sodalite, calcite, and pyrite) |
| Color | Deep blue with golden flecks of pyrite and white veins of calcite. |
| Streak | Yellow-Brown |
| Luster | Vitreous to greasy. |
| Transparency | Opaque. |
| Occurrence | Afghanistan, Chile, and Russia. |
| Formation | Formed from limestone subjected to high temperatures and pressures. |
| Diaphaneity | Opaque |
| Cleavage | None |
| Mohs Hardness | 5 to 5.5. |
| Specific Gravity | Approximately 2.7-2.9. |
| Diagnostic Properties | Intense blue color with pyrite inclusions. |
| Chemical Composition | (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2 |
| Pleochroism | Not exhibited in Lapis Lazuli. |
| Crystal System | Cubic (major mineral Lazurite) |
| Optical Properties | Aggregate (multiple minerals, so optical properties vary) |
| Refractive Index | 1.500 (approximate, varies due to mixture of minerals) |
| Birefringence | Varies due to mixture of minerals |
| 2V angle | Not applicable (mixture of minerals) |
| Dispersion | Not typically relevant for Lapis Lazuli. |