Kyanite
Kyanite is really a gem that is gorgeous differs in color from pale blue to very dark blue to green and hardly ever yellowish or pink. Crystals from Brazil may have both blue and zoned lengthwise that is green. A discover that is recent Tanzania has produced stunning orange crystals. The blue variety is most common and may also have breathtaking color that is sapphire-blue. Kyanite is somewhat rare as being a gem that is faceted to its perfect clevage and extreme variability in hardness in numerous instructions. Kyanite is trimorphous with Andalusite and Sillimanite meaning all three share the same chemical that is basic but have different crystal structures. Notable sources of treasure material are Minas Gerais, Brazil, Nepal, Loliondo, Tanzania and Tibet.
Distribution: Widely distributed, even yet in good crystals. From Mt. Greiner, Zillertal, Tirol, Austria. At Alpe Sponda, Pizzo Forno, and at Alpe Campolungo, Tessin, Switzerland. Into the Pfitschtal, Trentino-Alto Adige, Italy. From Röros, Norway. Around Yekaterinburg (Sverdlovsk), Ural Mountains, Russia. At Elovyi, Klavoloke, Karelia. From Sultan Hamud, Machakos district, Kenya. Big crystals from a true wide range of localities in Minas Gerais, Brazil, as at Barro Prêto, São José do Jacuri. Gorgeous orange crystals from Nani, Loliondo, Arusha area, Tanzania. In america, at Lyme, Grafton County, New Hampshire; at Judd’s Bridge, Litchfield County, Connecticut; at Darby, Delaware County, Pennsylvania; from near Bakersville, Mitchell County, and near Burnsville, Yancy County, North Carolina; on Willis hill, Buckingham County, Virginia.
| Chemical Formula: | Al2SiO5 |
| Aluminum Silicate | |
| Molecular Weight: | 162.05 gm |
| Composition: | Aluminum | 33.30 % | Al | 62.92 % | Al2O3 |
| Silicon | 17.33 % | Si | 37.08 % | SiO2 | |
| Oxygen | 49.37 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Triclinic – Pinacoidal |
| Crystal Habit: | Crystals bladed and tabular, elongated, to 0.5 m; typically bent or twisted |
| Twinning: | Lamellar common |
| Cleavage: | Perfect on {100}, good on {010}, (100) ^ (010) = 79°; parting on {001} |
| Fracture: | Splintery |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.5 – 7.0 (varies with direction) |
| Density: | 3.53 – 3.65 (g/cm3) |
| Luminescence: | Not Fluorescent |
| Radioactivity: | Not Radioavtive |
| Color: | Blue, Green, Yellow, Orange, Pink, White, Black; can be zoned |
| Transparency: | Transparent, Translucent |
| Luster: | Vitreous, Pearly |
| Refractive Index: | 1.712 – 1.734 Biaxial ( – ) |
| Birefringence: | 0.0150 – 0.0160 |
| Dispersion: | Weak; r > v; 0.020 |
| Pleochroism: | Weak; X = colorless, Y = violet-blue, Z = cobalt blue |
