Preisingerite is a rare secondary bismuth arsenate mineral typically found in the oxidation zones of bismuth-bearing ore deposits. It occurs as small, delicate platy or acicular crystals often grouped in radial clusters, requiring magnification for proper identification.
Is this preisingerite?
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 preisingerite with a known reference. Preisingerite sits at Mohs 3.5-4.5, 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: subadamantine to adamantine.
- 4Match the color rangeCompare against the expected color range: gray white, yellow gray.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, radial aggregates, crusts.
Often confused with
Preisingerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Preisingerite leaves white, Walpurgite leaves pale brownish yellow; luster reads subadamantine to adamantine on Preisingerite and adamantine to greasy on Walpurgite.
How to tell apart: Streak differs, so Preisingerite leaves white, Mixite leaves pale bluish green; luster reads subadamantine to adamantine on Preisingerite and vitreous, silky in aggregates on Mixite.
Often found alongside preisingerite
Minerals reported to co-occur with preisingerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Bi₃O(AsO₄)₂(OH)
- Mohs hardness
- 3.5-4.5
- Density
- 7.24 g/cm³
- Colors
- Streak
- White
- Luster
- Subadamantine to adamantine
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Platy crystals, radial aggregates, crusts
- Cleavage
- One, indistinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidized zone of some arsenic-bearing hydrothermal mineral deposits
Where rockhounds find preisingerite
Classic worldwide localities
- Mammoth mine, Tintic district, Juab Co., Utah, USA
- San Francisco de los Andes and Cerro Negro de la Aguadita Bi–As–Cu deposits, San Juan Province, Argentina
- Tazna, Potosí, Bolivia
- Sauschwart mine, Schneeberg, and at Mühlleithen, Saxony, Germany
- Black Forest, at the Clara mine, near Oberwolfach, from the Schmiedestollen, near Wittichen, in the Ödsbach Valley, near Oberkirch, and at Neubulach, Germany
- Reichenbach, near Bensheim, Hesse, Germany
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidized zone of some arsenic-bearing hydrothermal mineral deposits. If you start seeing rooseveltite, mixite, beudantite in float, you are in the right ground. Typical habit: platy crystals, radial aggregates, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify preisingerite?+
Where is preisingerite found?+
Is preisingerite safe to handle?+
What rocks look like preisingerite?+
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Find preisingerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
