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, 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.
