Peretaite is a rare calcium-antimony sulfate mineral named after its type locality in Italy. It typically forms delicate, yellow to colorless tabular crystals or crusts in the oxidation zones of antimony-rich hydrothermal deposits.
Is this peretaite?
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 peretaite with a known reference. Peretaite sits at Mohs 3.5-4, 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: monoclinic. Typical habit: tabular.
Often confused with
Peretaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Peretaite is noticeably harder (Mohs 3.5-4 vs. 2-2.5); luster reads vitreous on Peretaite and resinous to subadamantine on Senarmontite.
How to tell apart: Luster reads vitreous on Peretaite and adamantine, pearly on cleavages on Valentinite.
How to tell apart: Stibiconite is the harder of the two (Mohs 5.5-7 vs. 3.5-4); streak differs, so Peretaite leaves white, Stibiconite leaves light yellow; luster reads vitreous on Peretaite and pearly, opaline, glassy to earthy on Stibiconite.
Often found alongside peretaite
Minerals reported to co-occur with peretaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaSb₄O₄(SO₄)₂(OH)₂(H₂O)₂
- Mohs hardness
- 3.5-4
- Density
- 4.06 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular
- Cleavage
- On {100}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Of rare occurrence, formed by the action of H2SO4 solutions on stibnite in the oxidized zone of a limestone-hosted hydrothermal antimony-bearing deposit
Where rockhounds find peretaite
Classic worldwide localities
- Pereta and Cetine mines, and at Micciano, near Larderello, Val di Cecina, Tuscany, Italy
Field-hunting tip
Where it forms: Of rare occurrence, formed by the action of H2SO4 solutions on stibnite in the oxidized zone of a limestone-hosted hydrothermal antimony-bearing deposit. If you start seeing stibnite, pyrite, kermesite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
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What rocks look like peretaite?+
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Find peretaite on the map
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