Algodonite
Algodonite is a copper arsenide mineral that is frequently associated with Domeykite and other copper arsenides and sometimes discovered as a mixture of these minerals, creating Mohawkite. Mohawkite is a mixture of Algodonite, Domeykite, arsenic-rich Copper and may contain other minerals such as silver, cobalt, nickel or iron. Mohawkite is not considered a mineral that is valid since it is a mix, or alloy-like coumpound. Mohawkite is usually combined with Quartz crystal clusters as observed in the picture near the top of this web page. This makes for a very cabochon that is attractive bright, metallic, brassy Mohawkite and white Quartz. Cabochons of Algodonite, Domeykite and Mohawkite are appealing and bright with metallic luster but will tarnish quickly and turn a drab brown and lose their luster. They have to be coated with lacquer or other finish that is protective prevent tarnishing. Faceted gems are beautiful when cut and polished to a luster that is high are rarely available. Algodonite and Domeykite are heat sensitive, and care should be exercised when cutting.
Algodonite had been named in 1859 by F. Field for the discovery locality during the Los Algodones Mine, Los Algodones district, El Arrayan, La Serena, Elqui Province, Coquimbo Region, Chile. Mohawkite is known as after the initially reported, and just, locality at the Mohawk Mine, Mohawk, Keweenaw County, Michigan, USA.
Algodonite distribution: in Chile, at the locality that is sort of Los Algodones Mine, near Coquimbo, and the Cerro de las Seguas, Rancagua, O’Higgins Province. At Corocoro, Bolivia. In the Kokito II mine, Neuquén Province, Argentina. In the United States Of America, in Michigan, from Keweenaw County, at the Mohawk, Pewabic, Seneca, Ahmeek, and Champion mines, and at Painesdale, Houghton County, also from Baraga County; in Colorado, from the Cashin mine, Montrose County. At Långban, Värmland, Sweden. In France, from the Roua copper mines, about 50 north that is km of, Alpes-Maritimes. At Tsumeb, Namibia. Into the Talmessi mine, 35 km west of Anarak, Iran.
| Chemical Formula: | Cu6As |
| Copper Arsenide | |
| Molecular Weight: | 456.20 gm |
| Composition: | Copper | 83.58 % | Cu | ||
| Arsenic | 16.42 % | As | |||
| 100.00 % |
| Cleavage: | None |
| Fracture: | Sub-Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 4.0; Vickers: VHN100= 245 – 302 kg/mm2 |
| Density: | 8.38 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Crystallography: | Hexagonal – Dihexagonal Dipyramidal |
| Crystal Habit: | As incrustations of minute highly distorted crystals; commonly massive and granular. |
| Twinning: | None |
| Other characteristics: | Non-magnetic, non-fluorescent |
| Color: | Steel-gray to silver-white, tarnishes dull on exposure; in polished section, bright cream-white. |
| Transparency: | Opaque |
| Luster: | Bright Metallic |
| Refractive Index: | R1–R2: (400) 51.5–49.3, (420) 52.3–50.5, (440) 52.8–52.4, (460) 53.4–54.6, (480) 54.2–56.4, (500) 55.7–58.4, (520) 57.5–60.5, (540) 58.9–62.3, (560) 60.0–63.8, (580) 60.8–64.8, (600) 61.1–65.5, (620) 61.6–66.1, (640) 61.9–66.5, (660) 62.3–66.7, (680) 62.8–66.9, (700) 63.4–67.1 |
| Birefringence: | None (opaque) |
| Dispersion: | n/a |
| Pleochroism: | n/a |
| Anisotropism: |
Weak; color in reflected light: bright cream-white |
