Valentinite is a secondary mineral that typically forms as an oxidation product of stibnite in hydrothermal veins. Collectors look for its characteristic adamantine luster and bladed or tabular crystal habits, which are often found in crusts or radiating aggregates.
Is this valentinite?
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 valentinite with a known reference. Valentinite sits at Mohs 2.5-3, 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: adamantine, pearly on cleavages.
- 4Match the color rangeCompare against the expected color range: brownish reddish, colorless, gray white, grayish, yellowish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: divergent, euhedral crystals, striated.
Often confused with
Valentinite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads adamantine, pearly on cleavages on Valentinite and resinous to subadamantine on Senarmontite.
How to tell apart: Streak differs, so Valentinite leaves white, Stibnite leaves lead-gray; luster reads adamantine, pearly on cleavages on Valentinite and metallic, splendent on cleavage surfaces on Stibnite.
How to tell apart: Luster reads adamantine, pearly on cleavages on Valentinite and vitreous; pearly on cleavage surfaces on Claudetite.
Often found alongside valentinite
Minerals reported to co-occur with valentinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Sb₂O₃
- Mohs hardness
- 2.5-3
- Density
- 5.76 g/cm³
- Colors
- Streak
- White
- Luster
- Adamantine, pearly on cleavages
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Divergent, euhedral crystals, striated
- Cleavage
- {110}, perfect; {010}, imperfect
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- An alteration product of antimony-bearing minerals in the oxidized zone of hydrothermal antimony deposits
Where rockhounds find valentinite
Classic worldwide localities
- Chalanches mine, near Allemont, Isère, France
- Bräunsdorf, near Freiberg, Saxony, Germany
- Příbram, Czech Republic
- Pernek, near Pezinok, Slovakia
- Baia Sprie (Felsőbánya), Romania
- Cetine mine, 20 km southwest of Siena, Tuscany, Italy
Field-hunting tip
Where it forms: An alteration product of antimony-bearing minerals in the oxidized zone of hydrothermal antimony deposits. If you start seeing stibnite, antimony, stibiconite in float, you are in the right ground. Typical habit: divergent, euhedral crystals, striated. Train your eye for that shape before scanning the outcrop.
Common questions
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Find valentinite on the map
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