Creaseyite is a rare secondary mineral found in the oxidation zones of lead-copper mines. It typically occurs as delicate, bright green acicular or fibrous tufts and radiating sprays on a matrix of heavier lead ores.
Is this creaseyite?
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 creaseyite with a known reference. Creaseyite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light green.
- 3Read the lusterHold the specimen under a strong light. Luster: silky.
- 4Match the color rangeCompare against the expected color range: green, yellowish green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous, spherical.
Often confused with
Creaseyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Duftite is the harder of the two (Mohs 4.5 vs. 2.5); streak differs, so Creaseyite leaves light green, Duftite leaves pale green to white; luster reads silky on Creaseyite and dull to vitreous on fractures on Duftite.
How to tell apart: Conichalcite is the harder of the two (Mohs 4.5 vs. 2.5); streak differs, so Creaseyite leaves light green, Conichalcite leaves green; luster reads silky on Creaseyite and vitreous to somewhat greasy on Conichalcite.
How to tell apart: Malachite is the harder of the two (Mohs 3.5-4 vs. 2.5); streak differs, so Creaseyite leaves light green, Malachite leaves pale green; luster reads silky on Creaseyite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
Often found alongside creaseyite
Minerals reported to co-occur with creaseyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂Pb₂Fe₂Si₅O₁₇·6H₂O
- Mohs hardness
- 2.5
- Density
- 4.1 g/cm³
- Colors
- Streak
- Light green
- Luster
- Silky
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous, spherical
- Cleavage
- Poor on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidized zone of a base-metal deposit, in andesite breccia loosely cemented with iron oxides and wulfenite (Tiger, Arizona, USA)
Where rockhounds find creaseyite
Classic worldwide localities
- Gold Point, Esmeralda Co., Nevada, USA
- Caborca and Munihuaza, near Alamos, Sonora, Mexico
- Cruz del Sur mine, Rio Negro Province, Argentina
Field-hunting tip
Where it forms: In the oxidized zone of a base-metal deposit, in andesite breccia loosely cemented with iron oxides and wulfenite (Tiger, Arizona, USA). If you start seeing mimetite, dioptase, fluorite in float, you are in the right ground. Typical habit: fibrous, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
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Find creaseyite on the map
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