Brushite is a phosphate mineral primarily forming through the alteration of guano deposits in arid environments or caves. It often appears as small, fragile, tabular or bladed white crystals that require careful handling due to their low hardness and sensitivity to hydration changes.
Is this brushite?
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 brushite with a known reference. Brushite 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. Brushite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Brushite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, pale pink.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, bladed, sometimes massive or earthy.
Often confused with
Brushite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside brushite
Minerals reported to co-occur with brushite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaHPO₄·2H₂O
- Mohs hardness
- 2.5
- Density
- 2.33 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Bladed, Sometimes Massive or Earthy
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Guano Deposits in Caves or Oceanic Islands
- Typical price
- $10-50 per specimen
Where rockhounds find brushite
Classic worldwide localities
- Palau
- Christmas Island
- Mono Lake, California
- Czech Republic
Field-hunting tip
Look in guano deposits in caves or oceanic islands country — that is the host setting where brushite typically forms. If you start seeing gypsum, apatite, monetite in float, you are in the right ground. Field specimens usually show a tabular crystals, bladed, sometimes massive or earthy habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find brushite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
