Digenite
Digenite is a copper that is an unusual mineral that can be an important ore of Copper. It is not well known by treasure or mineral collectors due to the lack of good crystal formations, shortage of brilliant colors and it’s also easily confused with other copper sulfides. Despite these facts, faceted gems may be attractive with deep blue or black colors and lustre that is metallic.
Digenite is named from the Greek word “digenus” meaning “of two origins” or “sexes”, because of it’s relationship to Chalcocite and Covellite as a result of the assumed presence of both cuprous and ions being cupric. Digenite is found in copper sulfide deposits and is typically associated with and often intergrown with Chalcocite, Covellite, Djurleite, Bornite, Chalcopyrite and Pyrite. The type locality is Sangerhausen, Thuringia, Germany, in copper slate deposits.
Digenite is located of them costing only a couple of localities global. From Sangerhausen, Thuringia, Germany [TL]. In the Botallack mine, St. Just, Cornwall, and from Seathwaite Tarn, near Coniston, Cumbria, England. At Listulli, Norway. From Kiruna, Sweden. The Magma mine, Superior, Pinal County, as well as Bisbee, Cochise County in the USA, crystallized at Butte, Silver Bow County, Montana; in Arizona, from the United Verde mine, Jerome, Yavapai County. Abundant at Kennicott, Alaska. From Cananea, Sonora, Mexico. In Namibia, at Tsumeb. At Dongxiang, Jiangxi Province, Asia. Probably not yet recognized at many other localities.
| Category: | Sulfide mineral |
| Chemical Formula: | Cu9S5 |
| Copper Sulfide | |
| Molecular Weight: | 732.24 gm |
| Composition: | Copper | 78.10 % | Cu | ||
| Sulfur | 21.90 % | S | |||
| 100.00 % |
| Crystallography: | Trigonal – Hexagonal Scalenohedral |
| Crystal Habit: | Rarely in pseudocubic crystals, to 3 cm; more commonly as intergrowths with other copper sulfides. |
| Twinning: | None |
| Cleavage: | Distinct/Good on {111} (on synthetic material) |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 2.5 – 3.0 |
| Density: | 5.546 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Blue to Black; distinctly Blue in polished section. |
| Transparency: | Opaque |
| Luster: | Metallic |
| Refractive Index: | R: (400) 29.6, (420) 28.8, (440) 28.0, (460) 27.0, (480) 25.9, (500) 24.8, (520) 23.5, (540) 22.2, (560) 21.0, (580) 19.9, (600) 18.9, (620) 18.0, (640) 17.2, (660) 16.3, (680) 15.5, (700) 14.8 |
| Birefringence: | 0.000 (mostly Isotropic) |
| Pleochroism: | None |
| Anisotrophism: | Mostly Isotropic. Color in reflected light: Blue |
