Anorthoroselite is a rare cobalt arsenate mineral that forms as a triclinic polymorph of roselite. It is primarily found in association with secondary cobalt minerals in hydrothermal veins, typically appearing as delicate rose-colored crystal sprays or crusts.
Is this anorthoroselite?
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 anorthoroselite with a known reference. Anorthoroselite 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. Anorthoroselite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Anorthoroselite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: rose-red, pink, magenta.
- 5Look at form & habitCrystal system: triclinic. Typical habit: prismatic to acicular crystals, often as radial aggregates.
Often confused with
Anorthoroselite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Anorthoroselite is noticeably harder (Mohs 3.5 vs. 1.5-2.5); streak differs — Anorthoroselite leaves white, Erythrite leaves pale pink; luster reads vitreous on Anorthoroselite and adamantine to pearly on Erythrite.
Often found alongside anorthoroselite
Minerals reported to co-occur with anorthoroselite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Co(AsO₄)₂·2H₂O
- Mohs hardness
- 3.5
- Density
- 3.55 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Prismatic to Acicular Crystals, Often as Radial Aggregates
- Cleavage
- Good On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Cobalt-nickel-arsenic Deposits
- Typical price
- $50-500 depending on crystal size and matrix quality
Where rockhounds find anorthoroselite
Classic worldwide localities
- Bou Azzer (Morocco)
- Schneeberg (Germany)
Field-hunting tip
Look in hydrothermal cobalt-nickel-arsenic deposits country — that is the host setting where anorthoroselite typically forms. If you start seeing erythrite, dolomite, quartz in float, you are in the right ground. Field specimens usually show a prismatic to acicular crystals, often as radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find anorthoroselite on the map
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