Collophane is a massive, cryptocrystalline variety of apatite that serves as the primary mineral constituent of phosphorite and fossil bones. It typically occurs in earthy, botryoidal, or massive formations and is often found in marine sedimentary deposits rich in phosphate.
Is this collophane?
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 collophane with a known reference. Collophane sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Collophane leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Collophane typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: white, gray, yellow, brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive.
Often confused with
Collophane vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside collophane
Minerals reported to co-occur with collophane. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₅(PO₄,CO₃)₃(OH,F)
- Mohs hardness
- 5
- Density
- 2.7-3.2 g/cm³
- Streak
- White
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Scientific
- Host rock
- Sedimentary Deposits
- Typical price
- $5-30 specimen
Where rockhounds find collophane
2 mapped spotsClassic worldwide localities
- Florida, USA
- Morocco
- Christmas Island
- Nauru
Field-hunting tip
Look in sedimentary deposits country — that is the host setting where collophane typically forms. If you start seeing calcite, dolomite, quartz in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah — start trip planning there.
Common questions
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Find collophane on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
