Jeremejevite
Jeremejevite ended up being initially discovered on Mt. Soktui in Russia as minute crystals not adequate for faceting. More recent discovers at “Mile 72” near Khan River, north of Swakopmund, Namibia together with Eifel district in Germany have yielded beautiful pale crystals that are blue. The crystals are elongated and very small. Therefore, gems are small and often faceted in an emerald that is elongated baguette cut. Faceted Jeremejevite is extremely rare because most sources have produced a product that is little is mined out. Jeremejevite is also piezoelectric.
Jeremejevite is available to them costing only a localities being few. From Mt. Soktui, Nerschinsk district, Adun-Chilon Mountains, Siberia, Russia. Within the Kukurt massif, Pamir Mountains, Tajikistan. Relatively large crystals have been available at a prospect near Cape Cross, at Mile 72, about 100 north that is kilometre of, and from Ameib, Erongo Mountains, Namibia. At Wannerköpfe and Emmelberg, near Üdersdorf, Eifel district, Germany.
| Category: | Borate mineral |
| Chemical Formula: | Al6B5O15(F, OH)3 |
| Aluminum Borate Fluoride Hydroxide | |
| Molecular Weight: | 511.93 gm |
| Composition: | Aluminum | 31.62 % | Al | 59.75 % | Al2O3 |
| Boron | 10.56 % | B | 34.00 % | B2O3 | |
| Hydrogen | 0.10 % | H | 0.88 % | H2O | |
| Oxygen | 48.44 % | O | |||
| Fluorine | 9.28 % | F | 9.28 % | F | |
| – % | F | -3.91 % | — O=F2 | ||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Hexagonal – Dipyramidal |
| Crystal Habit: | Crystals are typically hexagonal prismatic, may be tapered by vincinal forms, with pyramidal termination, to 10 cm. |
| Twinning: | None |
| Cleavage: | None observed |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 6.5 – 7.5 |
| Density: | 3.28 – 3.31 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Other: | Piezoelectric |
| Color: | Colorless, pale to dark cornflower Blue, pale Yellowish Brown; Colorless to pale Blue in transmitted light, typically sector zoned. |
| Transparency: | Transparent |
| Luster: | Vitreous |
| Refractive Index: | 1.640 – 1.653 Uniaxial ( – ); may be anomalously Biaxial ( – ) in sector-zoned crystals |
| Birefringence: | 0.0130 |
| Dispersion: | Distinct; r > v |
| Pleochroism: | Light blue/colorless to light yellow |
