Jamesonite
Jamesonite is one of a sulfide that is few that form fine acicular crystals that appear as hair-like fibres. Jamesonite also types larger crystals which are prismatic are confused with Stibnite. Jamesonite is called feather ore and antimony that is grey. Jamesonite is rarely available as inclusions in Quartz cabochons. This material is available from Minas Gerais, Brazil.
Jamesonite can be obtained from many localities, but just a few have provided material that is rich. From Cornwall, England, around St. Endellion [TL] and St. Kew. In Germany, at Freiberg, Saxony; and near Magdesprung, Selke Valley, and Clausthal, Harz Mountains. From Príbram, Czech Republic. At Aranyidka, Baia Sprie (Felsöbánya), and Herja (Kisbánya), Baia Mare (Nagybánya) district, Romania. From Trepca, Serbia. At Sala, Västmanland, Sweden. From Machacamarca, Poopó, and Huanuni, Oruro, Bolivia. In Mexico, through the Noche Buena mine, near Mazapil; the Santa Rita mine, Nieves; and in relatively crystals that are thick the Noria mine, near Sombrerete, Zacatecas. In the USA, in Idaho, at Slate Creek, Shoshone County From the Dachang district, Guangxi Autonomous Region, Asia.
| Chemical Formula: | Pb4Fe2+Sb6S14 |
| Lead Iron Antimony Sulfide | |
| Molecular Weight: | 2,064.07 gm |
| Composition: | Iron | 2.71 % | Fe | ||
| Antimony | 35.39 % | Sb | |||
| Lead | 40.15 % | Pb | |||
| Sulfur | 21.75 % | O | |||
| 100.00 % |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Crystals elongated || [001], acicular and fibrous, to 10 cm; striated k [001]; rarely in rings and spheres. As feltlike masses; massive, columnar, also radial and plumose. |
| Twinning: | On {100}; lamellae very commonly observed in polished section. |
| Cleavage: | Good on {001}; reported on {010} and {120} |
| Fracture: | n/a |
| Tenacity: | Brittle |
| Moh’s Hardness: | 2.5; VHN = 66–86 (100 g load) |
| Density: | 5.63 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Gray-Black, lead Gray, Steel Gray, dark lead Gray; iridescent at times |
| Transparency: | Opaque |
| Luster: | Metallic |
| Refractive Index: | R1–R2: (400) 38.4–45.1, (420) 38.1–44.9, (440) 37.7–44.8, (460) 37.6–45.0, (480) 37.4–45.1, (500) 37.3–45.0, (520) 37.0–44.7, (540) 36.6–44.3, (560) 36.1–43.8, (580) 35.7–43.2, (600) 35.3–42.6, (620) 34.8–41.9, (640) 34.2–41.0, (660) 33.6–40.1, (680) 33.0–39.2, (700) 32.5–38.5 |
| Pleochroism: | Distinct |
| Anisotrophism: | Strong; Color in reflected light: Gray-Black |
