Mosandrite
Mosandrite is an extremely rare gem that is a complex sorosilicate and is weakly radioactive due to its Cerium content. Mosandrite crystals are usually heavily included and very rarely found as gem quality. The main source of facetable crystals is Kukisvumchorr Mountain, Kola Peninsula, Murmansk District, Russia.
| Crystallography: | Monoclinic – Sphenoidal |
| Crystal Habit: | Crystals are Prismatic – Crystals Shaped like Slender Prisms |
| Twinning: | None |
| Cleavage: | [100] Good |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 4.0 |
| Density: | 3.29 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Weak; GRapi = 23,082.68 (Gamma Ray American Petroleum Institute Units) |
| Color: | Yellow, Yellowish green, Reddish brown, Brown |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous (glassy) |
| Refractive Index: | 1.646 – 1.658 Biaxial ( + ) |
| Birefringence: | 0.0120 |
| Dispersion: | Strong; r > v |
| Pleochroism: | None |
