Serendibite
Serendibite is a very rare gem that comes in colors of dark blue, blue green, light yellow and black. Most facetable crystals are very dark blue to opaque black. Although Serendibite is found in several locations around the world, the only current gem sources are Mogok, Sagaing District, Mandalay Division, Burma (Myanmar) and Gangapitiya, near Ambakotte, Sri Lanka. Other minor (and usually non-gem) sources are on the Melville Peninsula, Northwest Territories, Canada. In Russia, in the Tayozhnoye iron deposit, 550 km south of Yakutsk, Yakutia. From the Handeni district, Tanzania. At Ianapera and Ihosy, Madagascar. In the USA, from near Johnsburg, Warren County, Amity, near Warwick, Orange County, and Russell, St. Lawrence County, New York; and in the New City quarry, three km south of Riverside, Riverside County, California, USA.
| Category: | Inosilicates |
| Formula: | (Ca,Na)2(Mg,Fe2+)3(Al,Fe3+)3[O2|(Si,Al,B)6O18] |
| Crystallography: | Triclinic – Pinacoidal |
| Crystal Habit: | Rarely in small tabular crystals; as anhedral grains, to 2 cm, and aggregates. |
| Twinning: | Polysynthetic on [011], common |
| Cleavage: | [001] Good, [010] Good |
| Fracture: | Uneven, Conchoidal |
| Tenacity: | Brittle |
| Hardness (Mohs): | 6.5 – 7.0 |
| Density: | 3.42 – 3.52 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Grayish Blue-Green to deep Blue, Green, Brown or Black; in transmitted light, nearly Colorless to pale Yellow-Green or Blue |
| Transparency: | Transparent, Translucent, Opaque |
| Luster: | Vitreous |
| Refractive Index: | 1.701 – 1.706 Biaxial ( + ) |
| Birefringence: | 0.0050 |
| Dispersion: | r > v; Strong to extremely Strong, may produce abnormal interference colors |
| Pleochroism: | Strong; X = pale yellow, yellow-green to blue-green; Y = almost colorless, pale yellow, blue, blue-green; Z = light to dark blue |
