Aragonite
Aragonite is a member that is rare of Aragonite number of minerals that also includes Cerussite and Witherite. Aragonite is a breathtaking but little-seen gem and is certainly a collector that is a rare gem. It is too soft for jewellery wear and gems that are faceted usually really small. Aragonite is the second most typical polymorph of natural calcium carbonate, the being that is first. A polymorph implies that it offers similar chemical formula as Calcite but a crystal structure that is significantly different. Aragonite is usually created in limestone caverns, hot springs and the zone that is oxidised of build up.
The greatest current sources of gem quality Aragonite crystals are Bilin, Ústí Region, Bohemia, Czech Republic; Tazouta, Morocco; and Tsumeb, Namibia.
| Category: | Carbonate mineral |
| Chemical Formula: | CaCO3 |
| Calcium Carbonate | |
| Molecular Weight: | 100.09 gm |
| Composition: | Calcium | 40.04 % | Ca | 56.03 % | CaO |
| Carbon | 12.00 % | C | 43.97 % | CO2 | |
| Oxygen | 47.96 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE | |||
| Crystallography: | Orthorhombic – Dipyramidal |
| Crystal Habit: | Isolated Crystals short to long prismatic, also acicular with chisel-like terminations, dipyramidal, thick tabular, to 30 cm; as columnar crystal aggregates and crusts, globular, reniform, pisolitic, coralloidal, stalactitic, internally fibrous or banned. |
| Twinning: | Common by repeated contact twinning, yielding pseudohexagonal columnar trillings; also polysynthetic lamellae and striations. |
| Cleavage: | Distinct on {010}, Imperfect on {110} and {011} |
| Fracture: | Sub-Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.5 – 4.0 |
| Density: | 2.95 (g/cm3) |
| Luminescence: | Fluorescent; pale rose, yellow, white or bluish, with greenish or white phosphorescence under LWUV; yellowish under SW UV. Cathodoluminescent. |
| Radioactivity: | Not Radioactive pale rose, yellow, white or bluish, with greenish or white phosphorescence under LWUV; yellowish under SW UV. |
| Colour: | Colorless, White, also Gray, pale shades of Yellow, Blue, Violet, Green, Red; Colourless in transmitted light. |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous, Resinous on fracture surfaces |
| Refractive Index: | 1.530 – 1.685 Biaxial ( – ) |
| Birefringence: | 0.155 |
| Dispersion: | Weak; r < v |
| Pleochroism: | None |
