Matteuccite is a rare sulfate mineral typically found as a volcanic sublimated product in fumarole vents. Collectors should look for delicate, needle-like white or colorless crystals forming crusts; it is highly water-soluble and must be stored in a dry environment.
Is this matteuccite?
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 matteuccite with a known reference. Matteuccite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular or fibrous crystals, often as crusts or efflorescences.
Often confused with
Matteuccite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside matteuccite
Minerals reported to co-occur with matteuccite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaHSO₄·H₂O
- Mohs hardness
- 2
- Density
- 2.118 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular or fibrous crystals, often as crusts or efflorescences
- Cleavage
- Good on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In stalactites formed in a volcanic crater
Where rockhounds find matteuccite
Classic worldwide localities
- Vesuvius, Campania, Italy
Field-hunting tip
Where it forms: In stalactites formed in a volcanic crater. If you start seeing mercallite, ralstonite in float, you are in the right ground. Typical habit: acicular or fibrous crystals, often as crusts or efflorescences. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify matteuccite?+
Where is matteuccite found?+
What rocks look like matteuccite?+
What minerals are found with matteuccite?+
What kind of rock does matteuccite form in?+
What is matteuccite used for?+
Find matteuccite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
