Aiolosite is a rare sodium bismuth sulfate that forms colorless to white acicular to slender terminated prismatic crystals. It occurs in altered pyroclastic breccia in an active medium-temperature intracrater volcanic fumarole. It was first described from La Fossa Crater, Vulcano, Aeolian Islands, Sicily, Italy.
Is this aiolosite?
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 aiolosite with a known reference. Aiolosite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular to slender terminated prismatic crystals.
Often confused with
Aiolosite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside aiolosite
Minerals reported to co-occur with aiolosite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂(Na₂Bi)(SO₄)₃Cl
- Mohs hardness
- 3.5
- Density
- 3.589 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular to slender terminated prismatic crystals
- Rarity
- Rare
- Uses
- Collector
- Host rock
- On altered pyroclastic breccia in an active medium-temperature intracrater volcanic fumarole
Where rockhounds find aiolosite
Classic worldwide localities
- La Fossa Crater, Vulcano, Aeolian Islands, Sicily, Italy
Field-hunting tip
Where it forms: On altered pyroclastic breccia in an active medium-temperature intracrater volcanic fumarole. If you start seeing alunite, anhydrite, demicheleite- in float, you are in the right ground. Typical habit: acicular to slender terminated prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify aiolosite?+
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What rocks look like aiolosite?+
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Find aiolosite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
