Collinsite is a rare hydrated calcium magnesium phosphate typically found as radiating fibrous or spherulitic aggregates. It is often discovered within phosphate nodules or secondary cavities and is highly prized by collectors for its distinctive radial crystal habit.
Is this collinsite?
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 collinsite with a known reference. Collinsite 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. Collinsite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Collinsite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, yellowish-brown, tan, white.
- 5Look at form & habitCrystal system: triclinic. Typical habit: radiating fibrous masses, globular, spherulitic.
Often confused with
Collinsite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside collinsite
Minerals reported to co-occur with collinsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Mg(PO₄)₂·2H₂O
- Mohs hardness
- 3.5
- Density
- 3.1 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Radiating Fibrous Masses, Globular, Spherulitic
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate Nodules in Sedimentary Rocks or Hydrothermal Veins
- Typical price
- $20-150 per specimen depending on size and quality
Where rockhounds find collinsite
Classic worldwide localities
- British Columbia, Canada
- Yukon, Canada
- Bavaria, Germany
- South Australia, Australia
Field-hunting tip
Look in phosphate nodules in sedimentary rocks or hydrothermal veins country — that is the host setting where collinsite typically forms. If you start seeing apatite, vivianite, limburgite in float, you are in the right ground. Field specimens usually show a radiating fibrous masses, globular, spherulitic habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find collinsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
