Hydroxylwagnerite is a rare phosphate mineral occurring in granite pegmatites. It is visually similar to wagnerite and triplite, often requiring X-ray diffraction or chemical analysis for positive identification.
Is this hydroxylwagnerite?
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 hydroxylwagnerite with a known reference. Hydroxylwagnerite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: tan.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Hydroxylwagnerite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside hydroxylwagnerite
Minerals reported to co-occur with hydroxylwagnerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₂PO₄(OH)
- Mohs hardness
- ~5
- Density
- 3.074 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- Poor, two sets nearly perpendicular
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An accessory rock-forming mineral in quartz-rich, pyrope-kyanite-phengite schist lenses within metagranite in ultrahigh-pressure metamorphic rocks
Where rockhounds find hydroxylwagnerite
Classic worldwide localities
- Dora-Maira Massif, western Alps, Vallone di Gilba, Val Varaita, Piemonte, Italy
Field-hunting tip
Where it forms: An accessory rock-forming mineral in quartz-rich, pyrope-kyanite-phengite schist lenses within metagranite in ultrahigh-pressure metamorphic rocks. If you start seeing talc, clinochlore, kyanite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hydroxylwagnerite?+
Where is hydroxylwagnerite found?+
What rocks look like hydroxylwagnerite?+
What minerals are found with hydroxylwagnerite?+
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What is hydroxylwagnerite used for?+
Find hydroxylwagnerite on the map
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