Domeykite
Domeykite is a copper arsenide mineral that is frequently related to Algodonite and other copper arsenides and sometimes discovered as being a blend of these minerals, creating Mohawkite. Mohawkite is a combination of Algodonite, Domeykite, arsenic-rich Copper and may also include other minerals such as for instance silver, cobalt, nickel or iron. Mohawkite is perhaps not considered a mineral that is valid since it is a mixture, or alloy-like coumpound. Mohawkite is often blended with Quartz crystal clusters as seen in the image near the top of this site. This will make for a very cabochon that is attractive bright, metallic, brassy Mohawkite and bright 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 must be coated with lacquer or other coating that is protective counter tarnishing. Faceted gems are beautiful when cut and polished to a luster that is high are very rarely available. Algodonite and Domeykite are heat painful and sensitive, and care should be exercised when cutting.
Domeykite was named in 1845 by Wilhelm Haidinger in honor of the mineralogist that is polish-Chilean “Ignacio” Domeyko (1802-1889). Who was the general head(rector) of the University of Chile from 1867 to 1883. Mohawkite is known as after the originally reported, and just, locality during the Mohawk Mine, Mohawk, Keweenaw County, Michigan, USA.
Domeykite distribution: in Chile, from the locality that is kind the Los Algodones silver mine, near Coquimbo as well as San Antonio and Chañarcillo, near Copiapó, Atacama. From Corocoro, Bolivia. At Cerro de Paracatas, Tlachapa, Guerrero, Mexico. In the USA, through the Mohawk and Ahmeek mines, Keweenaw County, and in the Sheldon-Columbia mine, Portage Lake, Houghton County, Michigan; at the Cashin mine, Montrose County, Colorado; from Franklin, Sussex County, New Jersey. In Canada, on Michipicoten Island and at the Silver Islet mine, Thunder Bay, Lake Superior, Ontario; within the East Arm area, Great Slave Lake, Northwest Territories. From Långban and also at the Harstigen mine, Värmland, Sweden. From Wasserfall, about 20 km northwest of Belfort, Haute-Saône, and during the Roua copper mines, about 50 north that is kilometer of, Alpes Maritimes, France. From Zwickau, Saxony, and at Sailauf, northeast of Aschaffenburg, Bavaria, Germany. In the Condurrow mine, near Helstone, Cambourne, as well as Wheal Druid, Redruth, Cornwall, England. Within the Talmessi mine, 35 km western of Anarak, Iran. Several other occurrences are known.
| Chemical Formula: | Cu3As |
| Copper Arsenide | |
| Molecular Weight: | 265.56 gm |
| Composition: | Copper | 71.79 % | Cu | ||
| Arsenic | 28.21 % | As | |||
| 100.00 % |
| Crystallography: | Isometric – Hextetrahedral |
| Crystal Habit: | Reniform, botryoidal; massive. |
| Twinning: | None |
| Cleavage: | None |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.0 – 3.5; Vickers: VHN100= 213 – 235 kg/mm2 |
| Density: | 7.20 – 7.29 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Tin-white to steel-gray, tarnishes pale yellow, then pale brown, and finally to iridescence. |
| Transparency: | Opaque |
| Luster: | Metallic |
| Refractive Index: | R: (400) 41.1, (420) 41.4, (440) 41.7, (460) 43.1, (480) 45.2, (500) 47.5, (520) 49.3, (540) 50.7, (560) 52.2, (580) 53.6, (600) 54.5, (620) 54.9, (640) 54.8, (660) 54.6, (680) 54.4, (700) 54.6 R1–R2: (“domeykite-beta”): (400) 37.2–38.5, (420) 37.9–39.5, (440) 38.6–40.9, (460) 40.2–43.1, (480) 42.4–45.5, (500) 44.2–47.3, (520) 45.4–48.6, (540) 45.9–49.4, (560) 45.9–49.6, (580) 45.8–49.7, (600) 45.5–49.5, (620) 45.2–49.2, (640) 44.8–48.9, (660) 44.4–48.4, (680) 44.0–48.0, (700) 43.6–47.6 |
| Birefringence: | 0.000 (Isotropic) |
| Dispersion: | n/a |
| Pleochroism: | n/a |
| Anisotropism: | None |
