Chambersite
Chambersite is a borate that is rare and is the manganese analogue of Boracite. It is an mineral that is extremely unusual faceted gems are nearly non-existent. The tetrahedral shaped crystals are so(up that is small 10mm on the side) that Chambersite gems are usually not ‘cut’ nevertheless the surfaces of the natural crystal shape are just polished. Many crystals are too small and/or too dark to be faceted. Chambersite ended up being discovered in 1962 in a salt brine storage well at Barbers Hill Salt Dome (Barbers Hill), Mont Belvieu, Chambers County, Texas, USA. The way that only finds the tiny crystals is by diving to depths of up to 70 feet in the salt brine.
Distribution: In the USA, from the Barber’s Hill salt dome, Mont Belvieu, Chambers County, Texas (Type Locality) and the Venice salt dome, Plaquemines Parish, Louisiana. In the Jixian Mn–B deposits, Hebei Province, China. From Pomyarka, near Truskarets, Carpathian Mountains, Ukraine.
| Category: | Tektoborates |
| Chemical Formula: | Mn3B7O13Cl |
| Manganese Borate Chloride | |
| Molecular Weight: | 483.93 gm |
| Composition: | Manganese | 34.06 % | Mn | 43.98 % | MnO |
| Boron | 15.64 % | B | 50.35 % | B2O3 | |
| Chlorine | 7.33 % | Cl | 7.33 % | Cl | |
| – % | Cl | -1.65 % | -O=Cl2 | ||
| Oxygen | 42.98 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Orthorhombic – Pyramidal |
| Crystal Habit: | Crystals are pseudotetrahedral {111}, modified by {001}, {110}, and {111}, to 2 cm, paramorphous and composed of microscopically twinned aggregates of orthorhombic material inverted from the high-temperature form. |
| Twinning: | Rare as interpenetrant twins on [111] with twin plane {111} (pseudocubic). |
| Cleavage: | None |
| Fracture: | Subconchoidal to Irregular/Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 7.0 |
| Density: | 3.49 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Colorless, Lilac to dark Purple, Brownish Purple (may darken with exposure to sunlight) |
| Transparency: | Transparent to Opaque |
| Luster: | Vitreous (glassy) |
| Refractive Index: | 1.732 – 1.744 Biaxial ( + ) |
| Birefringence: | 0.0120 |
| Dispersion: | r > v |
| Pleochroism: | None |
