Vladimirite is a rare calcium arsenate mineral that typically forms striking white, rosette-like or radial crystal aggregates. It is almost exclusively found as a secondary mineral in oxidized zones of arsenic-rich hydrothermal deposits, often associated with other rare arsenate minerals.
Is this vladimirite?
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 vladimirite with a known reference. Vladimirite sits at Mohs 3.5, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless, light pink.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: radial aggregates, rosettes, crusts.
Often confused with
Vladimirite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Vladimirite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so Vladimirite leaves white, Pharmacosiderite leaves yellowish green; luster reads vitreous on Vladimirite and adamantine to greasy on Pharmacosiderite.
How to tell apart: Vladimirite is noticeably harder (Mohs 3.5 vs. 1.5-2); luster reads vitreous on Vladimirite and feeble pearly to silky on Picropharmacolite.
Often found alongside vladimirite
Minerals reported to co-occur with vladimirite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄(AsO₄)₂(AsO₃OH)·4H₂O
- Mohs hardness
- 3.5
- Density
- 3.14 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Radial aggregates, rosettes, crusts
- Cleavage
- One, good
- Rarity
- Rare
- Uses
- Collector, Mineralogical study
- Host rock
- A rare secondary mineral in the oxidized zone of arsenic-bearing mineral deposits
Where rockhounds find vladimirite
Classic worldwide localities
- Mohawk mine, Keweenaw Co., Michigan, USA
- Vladimirovskoye cobalt deposit, Altai Mountains, and the Khovu-Aksy Ni-Co deposit, Tuva, Siberia, Russia
- Bauhaus district, Richelsdorf Mountains, Hesse, Germany
- Irhtem (Ightem) mine, Bou Azzer district, Morocco
- Corbriza mine, Copiapó, Chile
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidized zone of arsenic-bearing mineral deposits. If you start seeing picropharmacolite, erythrite, aragonite in float, you are in the right ground. Typical habit: radial aggregates, rosettes, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
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Find vladimirite on the map
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