Felsőbányaite is a rare secondary sulfate mineral typically found as pearly white crusts or delicate platy aggregates within mine workings. It forms through the alteration of aluminum-bearing minerals in sulfide deposits and is highly prized by collectors for its fragile, tabular crystal habits.
Is this felsőbányaite?
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 felsőbányaite with a known reference. Felsőbányaite 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. Felsőbányaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Felsőbányaite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, tabular aggregates, pearly flakes.
Often confused with
Felsőbányaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside felsőbányaite
Minerals reported to co-occur with felsőbányaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₄SO₄(OH)₁₀·4H₂O
- Mohs hardness
- 2
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Tabular Aggregates, Pearly Flakes
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Mines
- Typical price
- $20-100 for small specimens
Where rockhounds find felsőbányaite
Classic worldwide localities
- Baia Sprie, Romania
- Bisbee, Arizona, USA
- Germany
- Poland
Field-hunting tip
Look in hydrothermal veins in mines country — that is the host setting where felsőbányaite typically forms. If you start seeing gypsum, alunite, pyrite in float, you are in the right ground. Field specimens usually show a platy crystals, tabular aggregates, pearly flakes habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify felsőbányaite?+
Where is felsőbányaite found?+
How much is felsőbányaite worth?+
What rocks look like felsőbányaite?+
What minerals are found with felsőbányaite?+
What kind of rock does felsőbányaite form in?+
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Find felsőbányaite on the map
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