Phoxite is a rare magnesium hydroxide that forms colorless blades. Associated minerals include antipinite, aphithitalite and bassanite. It was first described from depth (125 feet) in the Rowley mine, near Theba, Maricopa County, Arizona, USA.
Is this phoxite?
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 phoxite with a known reference. Phoxite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to oily.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: blades.
Often confused with
Phoxite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside phoxite
Minerals reported to co-occur with phoxite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)₂Mg₂(C₂O₄)(PO₃OH)₂(H₂O)₄
- Mohs hardness
- 2.5
- Density
- 1.98 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to oily
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Blades
- Cleavage
- Fair on (100)
- Rarity
- Rare
- Uses
- Collector
- Host rock
- phosphate-rich granite pegmatites
Where rockhounds find phoxite
Classic worldwide localities
- Rowley mine, Arizona, USA
Field-hunting tip
Where it forms: phosphate-rich granite pegmatites. If you start seeing antipinite, aphithitalite, bassanite in float, you are in the right ground. Typical habit: blades. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify phoxite?+
Where is phoxite found?+
What rocks look like phoxite?+
What minerals are found with phoxite?+
What kind of rock does phoxite form in?+
What is phoxite used for?+
Find phoxite on the map
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