Pumpellyite-(Fe3+) typically occurs as radiating sprays or fibrous masses within low-grade metamorphic environments. It is often identified by its characteristic deep green color and habit in amygdaloidal basalts, where it frequently forms alongside native copper or other secondary minerals.
Is this pumpellyite-(fe3+)?
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 pumpellyite-(fe3+) with a known reference. Pumpellyite-(Fe3+) sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pumpellyite-(Fe3+) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Pumpellyite-(Fe3+) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: green, brown, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, radiating, or massive aggregates.
Often confused with
Pumpellyite-(Fe3+) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside pumpellyite-(fe3+)
Minerals reported to co-occur with pumpellyite-(fe3+). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Fe³⁺Al₂(SiO₄)(Si₂O₇)(OH)₂·H₂O
- Mohs hardness
- 5.5-6
- Density
- 3.3-3.4 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Radiating, Or Massive Aggregates
- Cleavage
- Distinct in One Direction
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Metamorphic Rocks, Particularly Those Subjected to Low-grade Burial or Regional Metamorphism
- Typical price
- $10-50 for small specimens, up to $200 for high-quality clusters
Where rockhounds find pumpellyite-(fe3+)
Classic worldwide localities
- Keweenaw Peninsula, Michigan, USA
- Pirenópolis, Brazil
- Tadzhikistan
- New Zealand
- Italy
Field-hunting tip
Look in metamorphic rocks, particularly those subjected to low-grade burial or regional metamorphism country — that is the host setting where pumpellyite-(fe3+) typically forms. If you start seeing epidote, prehnite, chlorite in float, you are in the right ground. Field specimens usually show a fibrous, radiating, or massive aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify pumpellyite-(fe3+)?+
Where is pumpellyite-(fe3+) found?+
How much is pumpellyite-(fe3+) worth?+
What rocks look like pumpellyite-(fe3+)?+
What minerals are found with pumpellyite-(fe3+)?+
What kind of rock does pumpellyite-(fe3+) form in?+
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Find pumpellyite-(fe3+) on the map
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