Geerite is a very rare copper sulfide mineral typically found as microscopic grains within supergene enrichment zones. It is nearly impossible to distinguish from other copper sulfides like chalcocite without laboratory analysis such as X-ray diffraction or electron microprobe data. It is primarily a mineralogical curiosity for advanced collectors specializing in secondary copper ores.
Is this geerite?
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 geerite with a known reference. Geerite sits at Mohs 1.5-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Geerite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Geerite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: microscopic grains and aggregates.
Often confused with
Geerite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside geerite
Minerals reported to co-occur with geerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₈S₅
- Mohs hardness
- 1.5-2
- Density
- 5.5 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Microscopic Grains and Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Supergene Copper Sulfide Deposits
- Typical price
- $50-300 for rare micro-specimens
Where rockhounds find geerite
Classic worldwide localities
- Bristol, Connecticut, USA
- Chuquicamata, Chile
- Kidd Creek, Canada
Field-hunting tip
Look in supergene copper sulfide deposits country — that is the host setting where geerite typically forms. If you start seeing chalcocite, spionkopite, yarrowite in float, you are in the right ground. Field specimens usually show a microscopic grains and aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify geerite?+
Where is geerite found?+
How much is geerite worth?+
What rocks look like geerite?+
What minerals are found with geerite?+
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Find geerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
