Picropharmacolite is a rare calcium-magnesium arsenate that typically forms delicate, silky acicular tufts or crusts in oxidized mineral deposits. Due to its fragility and mineralogical rarity, it is highly prized by advanced collectors of secondary arsenate species.
Is this picropharmacolite?
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 picropharmacolite with a known reference. Picropharmacolite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Picropharmacolite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Picropharmacolite typically shows a silky luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: triclinic. Typical habit: acicular or fibrous tufts, crusts, or radiating groups.
Often confused with
Picropharmacolite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside picropharmacolite
Minerals reported to co-occur with picropharmacolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Mg(AsO₄)₂(AsO₃OH)₂·11H₂O
- Mohs hardness
- 2.5
- Density
- 2.56 g/cm³
- Streak
- White
- Luster
- Silky
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Acicular or Fibrous Tufts, Crusts, Or Radiating Groups
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Arsenic-rich Hydrothermal Mineral Deposits
- Typical price
- $20-150 thumbnail specimen
Where rockhounds find picropharmacolite
Classic worldwide localities
- Riechelsdorf, Germany
- Jáchymov, Czech Republic
- Ste-Marie-aux-Mines, France
Field-hunting tip
Look in oxidized zones of arsenic-rich hydrothermal mineral deposits country — that is the host setting where picropharmacolite typically forms. If you start seeing pharmacolite, arsenolite, picrovenite in float, you are in the right ground. Field specimens usually show a acicular or fibrous tufts, crusts, or radiating groups habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify picropharmacolite?+
Where is picropharmacolite found?+
How much is picropharmacolite worth?+
Is picropharmacolite safe to handle?+
What rocks look like picropharmacolite?+
What minerals are found with picropharmacolite?+
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Find picropharmacolite on the map
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