Enargite
Enargite is a copper that is somewhat unusual sulfide mineral that is dimorphous with Luzonite. What this means is the 2 minerals which have the chemical that is same (Cu3AsS4) but different crystal structures. Luzonite is Tetragonal and Enargite is Orthorhombic. Enargite doesn’t usually form well shaped crystals. Nevertheless, there are a few localities that create some fine Enargite clusters. It really is typically found as dark grey to black material that is massive. The crystals which are rare usually thick tabular, but may also be prismatic. Twinning is common for Enargite and can develop a star that is nice cyclic twin called a trilling. Enargite has a metallic to luster that is dull fairly soft with a Moh’s hardness of only 3.0.
Distribution: a mineral that is widespread could be an important ore of copper, but not commonly well-crystallized. Only a localities that are few be mentioned. In Peru, from Morococha [TL] and Cerro de Pasco, with exceptional crystals from the Mina Luz Angelica, Quiruvilca. In Argentina, in the Sierra de Famatina, La Rioja Province. In the Philippine Islands, at Mancayan, Luzon. From the Chinkuashi mine, Keelung, Taiwan. At Kaize-mura, Nagano Prefecture, and in the Teine mine, Hokkaido, Japan. In the USA, in splendent crystals from Butte, Silver Bow County, Montana; in Utah, within the Tintic District, Juab County; in Colorado, in fine specimens from a true range mines in debt hill district, San Juan County In Austria, at Matzenköpfl, Brixlegg, Tirol. From Bor, Serbia. In Italy, on Sardinia, at Alghero and Calabona. At Tsumeb, Namibia.
| Category: | Sulfide mineral |
| Chemical Formula: | Cu3AsS4 |
| Copper Arsenic Sulfide | |
| Molecular Weight: | 393.82 gm |
| Composition: | Copper | 48.41 % | Cu | ||
| Arsenic | 19.02 % | As | |||
| Sulfur | 32.57 % | S | |||
| 100.00 % |
| Crystallography: | Orthorhombic – Pyramidal |
| Crystal Habit: | Tabular on {001}; also prismatic by elongation of [001]; crystals up to 15 cm. Prism zone typically deeply striated k [001]. |
| Twinning: | Twin plane {320} common, rarely as interpenetrating pseudohexagonal trillings. |
| Cleavage: | Perfect on {110}, Distinct on {100} and {010}, Indistinct on {001} |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.0 |
| Density: | 4.45 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Health Warning: | Contains Arsenic – always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. |
| Color: | Grayish Black to iron-Black; in polished section, Gray to pale Pink-Brown; deep Red internal reflections may be observed. |
| Transparency: | Opaque |
| Luster: | Metallic to Dull |
| Refractive Index: | R1–R2: (400) 24.8–26.2, (420) 26.6–26.0, (440) 26.5–25.6, (460) 26.5–25.9, (480) 26.2–25.8, (500) 25.6–25.6, (520) 24.9–25.3, (540) 24.4–25.2, (560) 24.0–25.2, (580) 23.8–25.4, (600) 23.8–25.9, (620) 24.1–26.5, (640) 24.6–26.9, (660) 25.2–26.9, (680) 25.6–26.8, (700) 25.7–26.7 |
| Birefringence: | None; Opaque |
| Dispersion: | None |
| Pleochroism: | Weak |
| Anisotrophism: | Strong; dark violet red or olice green tones. Color in reflected light: grey to light pink brown. Internal reflections: deep red. |
