Pisanite is a hydrated iron-copper sulfate that typically forms as a secondary mineral in the oxidized zones of copper-rich sulfide ore bodies. Collectors should look for its distinctive blue to blue-green color, but be aware it is highly soluble and should be stored in a dry environment to prevent dehydration or efflorescence.
Is this pisanite?
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 pisanite with a known reference. Pisanite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pisanite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Pisanite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, efflorescent crusts, prismatic crystals.
Often confused with
Pisanite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside pisanite
Minerals reported to co-occur with pisanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Fe,Cu)SO₄·7H₂O
- Mohs hardness
- 2
- Density
- 1.9 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Efflorescent Crusts, Prismatic Crystals
- Cleavage
- Perfect in One Direction
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Oxidized Zones of Sulfide Ore Deposits
- Typical price
- $10-50 per specimen depending on size
Where rockhounds find pisanite
1 mapped spotsClassic worldwide localities
- Rio Tinto, Spain
- Chuquicamata, Chile
- Bisbee, Arizona, USA
- Mount Morgan, Australia
Field-hunting tip
Look in oxidized zones of sulfide ore deposits country — that is the host setting where pisanite typically forms. If you start seeing chalcanthite, melanterite, pyrite in float, you are in the right ground. Field specimens usually show a fibrous, efflorescent crusts, prismatic crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Montana — start trip planning there.
Common questions
How do you identify pisanite?+
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Find pisanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
