Xanthoxenite is a rare secondary phosphate mineral found primarily in weathered granite pegmatites. Collectors usually search for its characteristic yellow, radiating, or platy crystal habit, which forms as an alteration product of primary phosphate minerals like triphylite.
Is this xanthoxenite?
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 xanthoxenite with a known reference. Xanthoxenite 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: dull to slightly waxy.
- 4Match the color rangeCompare against the expected color range: brownish yellow, light yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, radial aggregates, crusts.
Often confused with
Xanthoxenite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Rockbridgeite is the harder of the two (Mohs 3.5-4.5 vs. 2.5); streak differs, so Xanthoxenite leaves white, Rockbridgeite leaves greenish gray; luster reads dull to slightly waxy on Xanthoxenite and vitreous to dull on Rockbridgeite.
How to tell apart: Phosphosiderite is the harder of the two (Mohs 3.5-4 vs. 2.5); luster reads dull to slightly waxy on Xanthoxenite and vitreous to subresinous on Phosphosiderite.
Often found alongside xanthoxenite
Minerals reported to co-occur with xanthoxenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Fe³⁺₂(PO₄)₄(OH)₂·3H₂O
- Mohs hardness
- 2.5
- Density
- 2.97 g/cm³
- Streak
- White
- Luster
- Dull to slightly waxy
- Transparency
- Semitransparent
- Crystal system
- Triclinic
- Crystal habit
- Platy crystals, radial aggregates, crusts
- Cleavage
- {010}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon alteration product of triphylite in complex zoned granite pegmatites
Where rockhounds find xanthoxenite
Classic worldwide localities
- Palermo #1 mine, near North Groton, Grafton Co., New Hampshire, USA
- Tip Top, Linwood, and White Elephant mines, near Custer, Custer Co., South Dakota, USA
- Champion mine, White Mountains, Mono Co., California, USA
- Dunton quarry, Newry, and on Black Mountain and Red Hill, Rumford, Oxford Co., Maine, USA
- Hühnerkobel, near Zwiesel, and at Hagendorf, Bavaria, Germany
- Přibyslavice and Otov, Czech Republic
Field-hunting tip
Where it forms: An uncommon alteration product of triphylite in complex zoned granite pegmatites. If you start seeing apatite, whitlockite, childrenite–eosphorite in float, you are in the right ground. Typical habit: platy crystals, radial aggregates, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify xanthoxenite?+
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What rocks look like xanthoxenite?+
What minerals are found with xanthoxenite?+
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Find xanthoxenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
