Szaibelyite
Szaibelyite, also known as Ascharite, is a very rare borate mineral that is rarely available as a faceted gem. A faceted gem is an oddity just for collectors. The mineral is usually opaque with a silky to dull luster and found in fairly unattractive colors of buff white to straw yellow.
Szaibelyite is found in small amounts at numerous localities worldwide, typically in saline or borate evaporite deposits.
| Chemical Formula: | MgBO2(OH) |
| Magnesium Borate Hydroxide | |
| Molecular Weight: | 84.44 gm |
| Composition: | Magnesium | 28.50 % | Mg | 47.26 % | MgO |
| Iron | 0.66 % | Fe | 0.85 % | FeO | |
| Boron | 12.80 % | B | 41.23 % | B2O3 | |
| Hydrogen | 1.19 % | H | 10.67 % | H2O | |
| Oxygen | 56.85 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | As flattened fibers or laths; in spheroidal aggregates, to 5 mm; typically as felted or matted fibrous aggregates. |
| Twinning: | On {100} |
| Cleavage: | None |
| Fracture: | Conchoidal or Fibrous |
| Tenacity: | Inflexible |
| Moh’s Hardness: | 3.0 – 3.5 |
| Density: | 2.62 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Other: | Slowly soluble in acids |
| Color: | White to Buff, Straw-Yellow; Colorless in transmitted light |
| Transparency: | Translucent to Opaque |
| Luster: | Silky to Dull |
| Refractive Index: | 1.530 – 1.740 Biaxial ( – ) |
| Birefringence: | 0.020 – 0.070 |
| Dispersion: | r > v |
| Pleochroism: | None |
