Cavansite
Cavansite is a mineral that is rare crystals that are constantly far too small for faceting and are too little even for cabochons. It’s mostly collected as mineral specimens for the breathtaking colour that is blue of radial crystals and spherulitic rosettes.
Cavansite was originally discovered near Owyhee Dam, Lake Owyhee State Park, Malheur County, Oregon, USA and later during the Chapman quarry, Columbia County, Oregon, USA. Cavansite has recently found as remarkable specimens from quarries around Wagholi, Poona region, Maharashtra, India.
| Category: | Silicate mineral |
| Chemical Formula: | CaV5+Si4O11·4(H2O) |
| Hydrated Calcium Vanadium Silicate | |
| Molecular Weight: | 451.42 gm |
| Composition: | Calcium | 8.88 % | Ca | 12.42 % | CaO |
| Vanadium | 11.28 % | V | 20.15 % | V2O5 | |
| Silicon | 24.89 % | Si | 53.24 % | SiO2 | |
| Hydrogen | 1.79 % | H | 15.96 % | H2O | |
| Oxygen | 53.16 % | O | |||
| 100.00 % | 101.77 % | = TOTAL OXIDE | |||
| Crystallography: | Orthorhombic – Dipyramidal |
| Crystal Habit: | As prismatic crystals, to 1 mm, elongated || [001]; dominant forms {110} and {101}; as spherulitic rosettes, to 5 mm. |
| Twinning: | None |
| Cleavage: | Good on {010} |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.0 – 4.0 |
| Density: | 2.21 – 2.31 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Brilliant Sky Blue, Dark Blue, Greenish Blue |
| Transparency: | Subtransparent to Transparent |
| Luster: | Vitreous |
| Refractive Index: | 1.542 – 1.551 Biaxial ( + ) |
| Birefringence: | 0.009 |
| Dispersion: | Weak to Extreme; r < v |
| Pleochroism: | Pronounced; X = colorless; Y = blue; Z = colorless |
