Burbankite
Burbankite is a very rare mineral that comes from one of the four most prolific mineral localities in the world: Mont Saint-Hilaire, Quebec, Canada. Burbankite crystals are quite small and faceted gems are extremely rare. Burbankite has some unusual chemistry as it is enriched with rare elements such as Strontium (Sr), Barium (Ba) and Cerium (Ce). It is also mildly radioactive as defined in 49 CFR 173.403 (greater than 70 Bq / gram).
The only source of gem quality crystals is the Poudrette quarry, Mont Saint-Hilaire, Rouville County, Québec, Canada. Other non-gem sources are in the USA, from vermiculite prospects at the head of Big Sandy Creek, Rocky Boy’s Indian Reservation, about 40 km east of Box Elder, Hill County, Montana; in the Green River Formation, Utah and Wyoming. In Canada, at Mont Saint-Hilaire, and in the Miron quarry, Montreal, Quebec; at Chipman Lake, Ontario. In the Qaqarssuk carbonatite, near Sukkertoppen, and the Grønnedal-Ika complex, Greenland. Found in Brazil, at Po¸cos de Caldas, Minas Gerais. In Russia, on the Kola Peninsula, from the Vuoriyarvi carbonatite and Khibiny massifs, large crystals; at the Ozernyi carbonatite, southeastern Sakha; Arbarastakh carbonatite, Aldan; and the Nizhnesayanskii carbonatite, east Sayan; and in the Vishnevogorsk complex, Vishnevy-Ilmen Mountains, Southern Ural Mountains. From the Tajno massif carbonatites, 70 km north of Bialystok, Poland. In the Zeerust district, Transvaal, South Africa.
| Chemical Formula: | (Na,Ca)3(Sr,Ba,Ce)3(CO3)5 |
| Sodium Calcium Strontium Barium Cerium Carbonate | |
| Molecular Weight: | 706.03 gm |
| Composition: | Barium | 17.51 % | Ba | 19.55 % | BaO |
| Sodium | 7.16 % | Na | 9.66 % | Na2O | |
| Strontium | 22.34 % | Sr | 26.42 % | SrO | |
| Calcium | 4.54 % | Ca | 6.35 % | CaO | |
| Ceruim | 5.95 % | Ce | 6.97 % | Ce2O3 | |
| Carbon | 8.51 % | C | 31.17 % | CO2 | |
| Oxygen | 33.99 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Hexagonal – Dihexagonal Dipyramidal |
| Crystal Habit: | Long dihexagonal prismatic crystals with shallow pyramidal terminations, striated parallel [001], may be in fibrous spherical aggregates; anhedral granular, to 5 cm. |
| Twinning: | None |
| Cleavage: | Distinct to Imperfect on {1010} |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.5 – 4.0 |
| Density: | 3.50 – 3.58 (g/cm3) |
| Luminescence: | Fluorescent |
| Radioactivity: | Mild; GRapi = 5,871.73 (Gamma Ray American Petroleum Institute Units) |
| Other: | Piezoelectric |
| Color: | Colorless, Grayish Yellow, pale Yellow, Orange, Pink, pale Greenish |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous |
| Refractive Index: | 1.616 – 1.623 Uniaxial ( – ) |
| Birefringence: | 0.0120 |
| Dispersion: | 0.013 |
| Pleochroism: | e = colorless, w = colorless |
