Mineralpedia Details for Enargite
Enargite
Named for the Greek word enargis, meaning “vivid,” for its distinct cleavage. Enargite is a common and widespread mineral that occurs locally as an important copper ore. A few localities for well crystallized material include in Peru, Argentina, the Philippines, Taiwan, Japan, the United States, Austria, Italy, and Namibia. Enargite occurs in hydrothermal vein deposits and as a late-stage mineral in low-temperature deposits.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/enargite.pdf
- Formula
- Cu3AsS4
- Crystal System
- Orthorhombic
- Crystal Habit
- Euhedral Crystals, Massive - Granular, Prismatic
- Cleavage
- Perfect, Distinct, Distinct
- Luster
- Metallic
- Color
- steel gray, blackish gray, violet black
- Streak
- black
- Class
- Orthorhombic - Pyramidal
- Fracture
- Uneven
- Hardness
- 3
- WebMineral
- View Enargite
- Mindat
- View Enargite
Enargite from Butte dist., Silver Bow Co., Montana, United States
- Special Info
- Phillips Collection
Silvery black striated 9mm Enargite crystals, which are distinct and well-formed. They are classic Enargite amongst good 5-13mm Pyrite crystals.
Also an ore specimen with long embedded Enargite crystals to 5cm. Enargite was widespread in the Butte mines. Enargite, a copper arsenic sulfide, is an important ore of copper, when found in large quantites since the arsenic content is a liability. Enargite accounted for 25-40% of Butte's copper production.
Last four photos are of a large heavy but almost pure crystalline mass of steely grey Enargite.
Enargite from Julcani mine, Julcani dist., Huancavelica dept., Peru
The specimen has been roughed up in places but represents a nice textbook Enargite with the largest crystal to 2cm.
Enargite from Longfellow mine, Red Mountain, San Juan Co., Colorado, United States
Great prismatic crystals of Enargite to 9mm with typical terminations. The average size is about 4mm.
Enargite from National Belle mine, Red Mountain, Ouray Co., Colorado, United States
1 to 2mm perfect Enargite crystals with the typical diamond-shaped terminations and luster. This piece exemplifies vein mineralization of sulfides and Quartz.
