Kentbrooksite
Kentbrooksite can be a mineral that is extremely uncommon is a manganese and fluorine rich member associated with the Eudialyte team of minerals with the formula (Na, REE)15(Ca, REE)6Mn3Zr3NbSi25O74F2·2H2O and crystal habit are Anhedral to subhedral aggregates to 2cm. The characteristic options of kentbrooksite, that create it totally different from eudialyte are (1) dominancy of F (2) dominancy of Mn, and (3) dominancy of Nb. It really is primarily available at Mt Saint-Hilaire, Quebec, Canada; Kangerlugssuaq Firth, Greenland; Telemark, Norway; Kola Peninsula, Russia; and Tien Shan Mts, Tajikistan. Gem quality crystals are excessively small and rare. Kentbrooksite contains Rare that is several worlds (REE) such as Lanthanum (La), Cerium (Ce), Praeseodymium (Pr), Neodymium (Nd) and Samarium (Sm) and for that reason is weakly radioactive as defined in 49 CFR 173.403 (greater than 70 Bq/gram).
| Category: | Silicate mineral, Cyclosilicate |
| Chemical Formula: | (Na,REE)15(Ca,REE)6Mn3Zr3NbSi25O74F2·2H2O |
| Crystallography: | Trigonal – Ditrigonal Pyramidal |
| Crystal Habit: | Anhedral to subhedral aggregates to 2cm |
| Twinning: | None |
| Cleavage: | None |
| Fracture: | Uneven |
| Tenacity: | Brittle |
| Hardness (Mohs): | 5.0 – 6.0 |
| Density: | 3.07 – 3.10 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Weak; GRapi = 29,710.44 |
| Color: | Yellowish Brown |
| Transparency: | Transparent, Translucent |
| Luster: | Vitreous |
| Refractive Index: | 1.623 – 1.628 Uniaxial ( – ) |
| Birefringence: | 0.005 |
| Dispersion: | Weak |
| Pleochroism: | None |
