Atencioite is a rare phosphate mineral member of the roscherite group, typically found as small bladed crystals or radiating clusters within complex pegmatite environments. It is chemically distinguished by its iron-rich composition compared to other group members and is primarily prized by advanced mineral collectors for its rarity.
Is this atencioite?
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 atencioite with a known reference. Atencioite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Atencioite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Atencioite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, greenish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, radial aggregates.
Often confused with
Atencioite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside atencioite
Minerals reported to co-occur with atencioite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Fe²⁺₂Be₄(PO₄)₄(OH)₄·6H₂O
- Mohs hardness
- 4
- Density
- 3.17 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Radial Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find atencioite
Classic worldwide localities
- Lavra do Cigano, Brazil
- Sapucaia pegmatite, Brazil
Field-hunting tip
Look in granite pegmatites country — that is the host setting where atencioite typically forms. If you start seeing quartz, albite, muscovite in float, you are in the right ground. Field specimens usually show a bladed crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find atencioite on the map
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