Sulphohalite
Sulphohalite is a rare sodium sulfate evaporite mineral that only occurs in three locations in the world; Namibia, Russia and California, USA. The most well known and best location for gemmy crystals is Searles Lake, San Bernardino County, California, USA. At Searles Lake Sulphohalite is associated with Halite and Hanksite.
Sulphohalite can be found at the Otjiwalundo salt pan, about 400 km west-northwest of Otavi, Namibia; from volcanoes on the Kamchatka Peninsula, Russia; and Searles Lake, San Bernardino County, California, USA.
| Chemical Formula: | Na6(SO4)2FCl | ||||||||||||||||||||||||||||||||||||||||
| Sodium Sulfur Fluorine Sulfate | |||||||||||||||||||||||||||||||||||||||||
| Molecular Weight: | 384.52 gm | ||||||||||||||||||||||||||||||||||||||||
| Composition: |
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| Crystallography: | Isometric – Hexoctahedral |
| Crystal Habit: | Octahedral, dodecahedral, cubic, or in combinations thereof, to 3 cm. |
| Twinning: | None |
| Cleavage: | {???} Perfect |
| Fracture: | Conchoidal to Sub-Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.5 |
| Density: | 2.489 – 2.50 (g/cm3) |
| Luminescence: | Fluorescent and Phosphorescent; bright white to creamy white under LW UV |
| Radioactivity: | Not Radioactive |
| Other: | Slowly soluble in cold water. |
| Color: | Colorless, Gray, Greenish Yellow; Colorless in transmitted light |
| Transparency: | Transparent |
| Luster: | Vitreous to Greasy (weak) |
| Refractive Index: | 1.455 Isotropic |
| Birefringence: | 0.0140 |
| Dispersion: | Very high |
| Pleochroism: | Very Strong |
| Anisotrophism: | Very Strong; Color in reflected light: |
