Enargite is a brittle copper-arsenic sulfosalt commonly found in intermediate-temperature hydrothermal veins. It is typically identified by its metallic grayish-black luster, perfect cleavage, and association with other sulfide minerals. Collectors prize well-formed, striated prismatic crystals from classic mining districts like Butte, Montana.
Is this enargite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch enargite with a known reference. Enargite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: grayish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic to dull.
- 4Match the color rangeCompare against the expected color range: grayish-black, iron-black, steel gray, blackish gray, violet black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: euhedral crystals, massive, prismatic.
Often confused with
Enargite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Enargite leaves grayish black, Tennantite leaves reddish gray.
How to tell apart: Streak differs, so Enargite leaves grayish black, Tetrahedrite leaves black to brown.
How to tell apart: Enargite is noticeably harder (Mohs 3 vs. 2); streak differs, so Enargite leaves grayish black, Stibnite leaves lead-gray.
Often found alongside enargite
Minerals reported to co-occur with enargite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃AsS₄
- Mohs hardness
- 3
- Density
- 4.45 g/cm³
- Colors
- Streak
- Grayish black
- Luster
- Metallic to dull
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Euhedral crystals, massive, prismatic
- Cleavage
- Perfect on {110}, distinct on {100} and {010}, indistinct on {001}
- Rarity
- Uncommon
- Uses
- Collector, Ore of copper
- Host rock
- In hydrothermal vein deposits formed at medium temperatures
Where rockhounds find enargite
Classic worldwide localities
- Butte, Silver Bow Co., Montana, USA
- Tintic district, Juab Co., Utah, USA
- A number of mines in the Red Mountain district, San Juan Co., Colorado, USA
- Morococha (type locality) and Cerro de Pasco, Mina Luz Angelica, Quiruvilca, Peru
- Sierra de Famatina, La Rioja Province, Argentina
- Philippine Islands, at Mancayan, Luzon
Field-hunting tip
Where it forms: In hydrothermal vein deposits formed at medium temperatures. If you start seeing pyrite, sphalerite, galena in float, you are in the right ground. Typical habit: euhedral crystals, massive, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
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Find enargite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
