Austinite
Austinite is a fairly rare mineral and an gem that is incredibly rare. Mineral specimens are very collectable as they happen as radial groups of colorless to intense emerald crystals that are green. Austinite forms in the oxidation zone of zinc ore deposits often associated with Adamite.
Austinite is situated in just a handful of localities. In the USA, at the locality that is type the Western Utah mine, Gold Hill, Tooele County, Utah; at the Mohawk mine, Clark Mountains, San Bernardino County, California; from the Table Mountain mine, Galiuro Mountains, Pinal County, Arizona; at Sterling Hill, Ogdensburg, Sussex County, New Jersey; in the Tucker’s tunnel uranium deposit, near Durango, Hinsdale County, Colorado. Through the Ojuela mine, Mapimi, Durango, Mexico. During the Lili mine, near Lomitos, Bolivia. From the Kamariza mine, Laurium, Greece. At Tsumeb and Guchab, Otavi district, Namibia. Within the Puttapa zinc mine, near Beltana, South Australia.
| Chemical Formula: | CaZn(AsO4)(OH) |
| Calcium Zinc Arsenate Hydroxide | |
| Molecular Weight: | 261.39 gm |
| Composition: | Calcium | 15.33 % | Ca | 21.45 % | CaO |
| Zinc | 25.02 % | Zn | 31.14 % | ZnO | |
| Arsenic | 28.66 % | As | 43.96 % | As2O5 | |
| Hydrogen | 0.39 % | H | 3.45 % | H2O | |
| Oxygen | 30.60 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Orthorhombic – Disphenoidal |
| Crystal Habit: | As enantiomorphous bladed crystals exhibiting {011}, {111}, {111}, {010} and several other forms, sometimes forming scepters. Also as radially fibrous crusts and nodules. |
| Twinning: | Left- and right-handed individuals joined on (100), with (010) and (001) coincident. |
| Cleavage: | Good on {011} |
| Fracture: | Irregular/Uneven, Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 4.0 – 4.5 |
| Density: | 4.13 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Colorless to pale Yellowish White or bright Green; Colorless in transmitted light. |
| Transparency: | Transparent to Translucent |
| Luster: | Sub-Adamantine, Silky in aggregates |
| Refractive Index: | 1.759 – 1.783 Biaxial ( + ) |
| Birefringence: | 0.0240 |
| Dispersion: | Weak; r > v |
| Pleochroism: | None |
