Hidalgoite is a rare member of the beudantite group, typically found as an oxidation product of primary lead ores. Collectors look for its small, often pale-colored tabular crystals which occur in weathered mineral zones alongside other lead arsenates.
Is this hidalgoite?
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 hidalgoite with a known reference. Hidalgoite sits at Mohs 4-4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hidalgoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hidalgoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellow, gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, crusts, massive.
Often confused with
Hidalgoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside hidalgoite
Minerals reported to co-occur with hidalgoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbAl₃(AsO₄)(SO₄)(OH)₆
- Mohs hardness
- 4-4.5
- Density
- 4.26 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Crusts, Massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Lead-arsenic Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find hidalgoite
Classic worldwide localities
- Hidalgo, Mexico
- Tsumeb, Namibia
- Black Forest, Germany
- Cumberland, England
Field-hunting tip
Look in oxidized hydrothermal lead-arsenic deposits country — that is the host setting where hidalgoite typically forms. If you start seeing anglesite, galena, mimetite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find hidalgoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
