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, 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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