Axinite-(Fe)
Axinite-(Fe) is a gem that is somewhat rare is usually extremely trichroic with brown and purple colors being dominant. Axinite-(Fe) may be the iron analog of Axinite-(Mg) which is the Magnesium analog. It is hard to find material without internal flaws and feathers. Despite the inclusions, Axinite is a treasure that is magnificent of its rich colors and brilliance.
There are lots of localities for Axinite-(Fe), also for fine crystals. On Roscommon Cliff and into the Botallack mine, St. Just, Cornwall, England. From Bourg d’Oisans, Isère, France. In the Maderantal, Uri, Switzerland. Extraordinary crystals from the Puiva deposit, about 100 km west-northwest of Saranpaul, Subpolar Ural Mountains; at Zlatoust, Ural Mountains; and somewhere else in Russia. At Skardu, Pakistan. Within the Obira mine, Bungo, Oita Prefecture; the Toroku mine, Miyazaki Prefecture; and elsewhere in Japan. In the USA, from Coarse Gold, Madera County, near Yreka, Siskiyou County, and New Melones Lake, Calaveras County, California; and from Elkhorn, Jefferson County, Montana. In Canada, found near Hope, British Columbia, and within the Moneta mine, Timmins, Ontario. From Trinidad, Baja Ca, Mexico. At Vitoria da Conquista, Bahia, Brazil.
| Category: | Sorosilicates |
| Chemical Formula: | Ca2Fe2+Al2(BO3)Si4O12(OH) |
| Calcium Iron Aluminum Boron Sorosilicate Hydroxide | |
| Molecular Weight: | 570.12 gm |
| Composition: | Calcium | 14.06 % | Ca | 19.67 % | CaO |
| Aluminum | 9.47 % | Al | 17.88 % | Al2O3 | |
| Iron | 9.80 % | Fe | 12.60 % | FeO | |
| Silicon | 19.71 % | Si | 42.16 % | SiO2 | |
| Boron | 1.90 % | B | 6.11 % | B2O3 | |
| Hydrogen | 0.18 % | H | 1.58 % | H2O | |
| Oxygen | 44.90 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Triclinic – Pinacoidal |
| Crystal Habit: | Crystals typically flattened, axe-head-shaped, to 20 cm; granular, massive. |
| Twinning: | None |
| Cleavage: | Distinct on {100}, Poor on {001} and {110} |
| Fracture: | Irregular/Uneven to Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 6.5 – 7.0 |
| Density: | 3.25 – 3.28 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Brown, Purplish blue, Gray, Greenish yellow |
| Transparency: | Transparent to Subtransparent |
| Luster: | Vitreous (Glassy) |
| Refractive Index: | 1.672 – 1.701 Biaxial ( – ) |
| Birefringence: | 0.0090 – 0.0110 |
| Dispersion: | Strong, r < v |
| Pleochroism: | X = colorless, yellow, light brown, yellow brown, or pale green; Y = colorless, deep yellow, deep blue, pale violet, or violet; Z = colorless, pale green, olive yellow, brown, or dark violet |
