Lapis lazuli
Rock / aggregate
Lapis lazuli is a deep-blue rock of lazurite with calcite and pyrite. It is a polycrystalline material rather than a single mineral species; its dominant component is Lazurite.
Photos
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About Lazurite (major)
Full reference data — crystallography, X-ray diffraction, and cited physical properties — is on the Lazurite species page.
| Formula | Na7Ca(Al6Si6O24)(SO4)(S3)-·H2O |
|---|---|
| Hardness (Mohs) | 5-5.5 |
| Specific gravity | 2.38-2.45 |
| Density (calculated) | 3.697 |
| Crystal system | cubic |
| Color range | blue, green, violet |
| Luster | vitreous |
About Calcite (minor)
Full reference data — crystallography, X-ray diffraction, and cited physical properties — is on the Calcite species page.
| Formula | Ca(CO3) |
|---|---|
| Hardness (Mohs) | 3 |
| Specific gravity | 2.713 |
| Density (calculated) | 2.694 |
| Crystal system | trigonal |
| Color range | black, blue, brown, colorless, gray, green, red, violet, white, yellow |
| Luster | earthy, vitreous |
| Streak | gray, white |
About Pyrite (minor)
Full reference data — crystallography, X-ray diffraction, and cited physical properties — is on the Pyrite species page.
| Formula | FeS2 |
|---|---|
| Hardness (Mohs) | 6-6.5 |
| Specific gravity | 4.95-5.1 |
| Density (calculated) | 5.016 |
| Crystal system | cubic |
| Color range | yellow |
| Luster | metallic |
| Streak | black, brown, green |