Erazoite is a rare copper tin sulfide, typically black. It was approved as a distinct mineral species in 2014. It was first described from the Chilena mine, Atacama desert, Antofagasta Province, Chile.
Is this erazoite?
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 erazoite with a known reference. Erazoite 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: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic to submetallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, crusts, aggregates.
Often confused with
Erazoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Erazoite is noticeably harder (Mohs ~3 vs. 1.5-2); streak differs, so Erazoite leaves black, Realgar leaves red-orange to red; luster reads metallic to submetallic on Erazoite and resinous to greasy on Realgar.
How to tell apart: Erazoite is noticeably harder (Mohs ~3 vs. 1.5-2); streak differs, so Erazoite leaves black, Orpiment leaves pale lemon-yellow; luster reads metallic to submetallic on Erazoite and resinous, pearly on cleavage surface on Orpiment.
Often found alongside erazoite
Minerals reported to co-occur with erazoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄SnS₆
- Mohs hardness
- ~3
- Density
- 4.53 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic to submetallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Tabular crystals, crusts, aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a high-sulfidation, epithermal vein deposit rich in gold, copper, and arsenic, with a strong influence of meteoric waters and hosted in volcanic rocks
Where rockhounds find erazoite
Classic worldwide localities
- Chilena mine, Soledad property, El Guanaco gold deposit, Atacama desert, Antofagasta Province, Chile
Field-hunting tip
Where it forms: In a high-sulfidation, epithermal vein deposit rich in gold, copper, and arsenic, with a strong influence of meteoric waters and hosted in volcanic rocks. If you start seeing barite, alunite, jarosite in float, you are in the right ground. Typical habit: tabular crystals, crusts, aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find erazoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
