Mcauslanite is an extremely rare phosphate mineral typically found as small, fragile yellowish white crystals in phosphate-rich environments. It is often discovered as an alteration product within nodules in sedimentary shales and requires careful handling due to its low hardness and delicate crystal structure.
Is this mcauslanite?
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 mcauslanite with a known reference. Mcauslanite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to silky.
- 4Match the color rangeCompare against the expected color range: yellowish white, colorless.
- 5Look at form & habitCrystal system: triclinic. Typical habit: bladed, fibrous, radial.
Often confused with
Mcauslanite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside mcauslanite
Minerals reported to co-occur with mcauslanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃Al₂(PO₄)₃(PO₃OH)F·18H₂O
- Mohs hardness
- 3.5
- Density
- 2.22 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to silky
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
- Crystal habit
- Bladed, fibrous, radial
- Cleavage
- Good on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A very rare non-oxidized secondary mineral along joints beneath the erosional surface of a greisen-hosted stockwork tin mine
Where rockhounds find mcauslanite
Classic worldwide localities
- East Kemptville tin mine, Yarmouth Co., Nova Scotia, Canada
Field-hunting tip
Where it forms: A very rare non-oxidized secondary mineral along joints beneath the erosional surface of a greisen-hosted stockwork tin mine. If you start seeing vivianite, phosphophyllite, childrenite–eosphorite in float, you are in the right ground. Typical habit: bladed, fibrous, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mcauslanite?+
Where is mcauslanite found?+
What rocks look like mcauslanite?+
What minerals are found with mcauslanite?+
What kind of rock does mcauslanite form in?+
What is mcauslanite used for?+
Find mcauslanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
