Fiemmeite is a rare copper oxalate mineral originally discovered in the copper-bearing sandstone deposits of the Fiemme Valley in Italy. It typically forms delicate, colorless to pale yellow platy crystals or crusts within the matrix of sedimentary rocks. Due to its extreme rarity and fragile nature, it is primarily sought after by advanced mineral collectors and those interested in organic-inorganic mineral species.
Is this fiemmeite?
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 fiemmeite with a known reference. Fiemmeite 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. Fiemmeite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fiemmeite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts, aggregates.
Often confused with
Fiemmeite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside fiemmeite
Minerals reported to co-occur with fiemmeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂(C₂O₄)(OH)₂·2H₂O
- Mohs hardness
- 2
- Density
- 2.28 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts, Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sedimentary (sandstone Hosted in Copper-rich Deposits)
- Typical price
- $50-300 per specimen
Where rockhounds find fiemmeite
Classic worldwide localities
- Fiemme Valley, Trentino-Alto Adige, Italy
Field-hunting tip
Look in sedimentary (sandstone hosted in copper-rich deposits) country — that is the host setting where fiemmeite typically forms. If you start seeing malachite, azurite, tenorite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fiemmeite?+
Where is fiemmeite found?+
How much is fiemmeite worth?+
Is fiemmeite safe to handle?+
What rocks look like fiemmeite?+
What minerals are found with fiemmeite?+
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Find fiemmeite on the map
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