Aluminopyracmonite is a rare ammonium aluminum sulfate mineral found primarily in volcanic fumarolic environments. It typically occurs as delicate, white to colorless crusts or efflorescences around active volcanic vents and is highly water-soluble.
Is this aluminopyracmonite?
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 aluminopyracmonite with a known reference. Aluminopyracmonite 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: 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: trigonal. Typical habit: crusts, efflorescences.
Often confused with
Aluminopyracmonite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside aluminopyracmonite
Minerals reported to co-occur with aluminopyracmonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)₃Al(SO₄)₃
- Mohs hardness
- 2.5
- Density
- 2.12 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Crusts, efflorescences
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A sublimate from medium-temperature (~250C̊) gases emanating from an intracrater volcanic fumarole
Where rockhounds find aluminopyracmonite
Classic worldwide localities
- La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy
Field-hunting tip
Where it forms: A sublimate from medium-temperature (~250C̊) gases emanating from an intracrater volcanic fumarole. If you start seeing adranosite, mascagnite, alunite in float, you are in the right ground. Typical habit: crusts, efflorescences. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify aluminopyracmonite?+
Where is aluminopyracmonite found?+
What rocks look like aluminopyracmonite?+
What minerals are found with aluminopyracmonite?+
What kind of rock does aluminopyracmonite form in?+
What is aluminopyracmonite used for?+
Find aluminopyracmonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
