Olsacherite is an exceptionally rare lead sulfate-selenate mineral discovered in the selenium-rich hydrothermal deposits of Argentina. Collectors should look for small, transparent to translucent crystals often associated with other rare selenium minerals in secondary oxidation zones.
Is this olsacherite?
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 olsacherite with a known reference. Olsacherite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Olsacherite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Olsacherite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, granular aggregates.
Often confused with
Olsacherite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside olsacherite
Minerals reported to co-occur with olsacherite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂(SeO₄)(SO₄)
- Mohs hardness
- 3-4
- Density
- 4.96 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals, Granular Aggregates
- Cleavage
- Distinct On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Sedimentary Sequences Enriched in Selenium
- Typical price
- $50-300+ per specimen depending on size and rarity
Where rockhounds find olsacherite
Classic worldwide localities
- Sierra de Cacheuta, Argentina
- Tintic District, Utah, USA
Field-hunting tip
Look in hydrothermal veins in sedimentary sequences enriched in selenium country — that is the host setting where olsacherite typically forms. If you start seeing clausthalite, selenite, chalcomenite in float, you are in the right ground. Field specimens usually show a tabular crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find olsacherite on the map
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