Wolfeite is a rare phosphate mineral typically found in complex granite pegmatites. It usually forms as reddish-brown, bladed to granular masses and is often difficult to distinguish visually from related species like triplite without chemical analysis.
Is this wolfeite?
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 wolfeite with a known reference. Wolfeite sits at Mohs 4.5-5, 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 if fibrous.
- 4Match the color rangeCompare against the expected color range: greenish, dark brown, reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed, prismatic, granular.
Often confused with
Wolfeite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside wolfeite
Minerals reported to co-occur with wolfeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₂PO₄(OH)
- Mohs hardness
- 4.5-5
- Density
- 3.79-3.82 g/cm³
- Streak
- White
- Luster
- Vitreous to silky if fibrous
- Transparency
- Opaque, transparent in small grains
- Crystal system
- Monoclinic
- Crystal habit
- Bladed, prismatic, granular
- Cleavage
- {100}, good; {120}, fair; {010}, poor; {110}, very poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral, formed by hydrothermal alteration of triphylite in complex zoned granite pegmatites; rarely in hydrothermal veins; in phosphatic nodules in shales
Where rockhounds find wolfeite
Classic worldwide localities
- Palermo #1 mine, near North Groton, and at the Keyes mine, Orange, Grafton Co., New Hampshire, USA
- Big Chief, Bull Moose, and Ross (Highland Lode) mines, near Custer, Custer Co., South Dakota, USA
- Big Fish River–Rapid Creek area, Yukon Territory, Canada
- Énio pegmatite mine, northeast of Galiléia, Minas Gerais, Brazil
- Hagendorf, Bavaria, Germany
- Congrier, Mayenne, France
Field-hunting tip
Where it forms: A secondary mineral, formed by hydrothermal alteration of triphylite in complex zoned granite pegmatites; rarely in hydrothermal veins; in phosphatic nodules in shales. If you start seeing triphylite, triplite, hagendorfite in float, you are in the right ground. Typical habit: bladed, prismatic, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify wolfeite?+
Where is wolfeite found?+
What rocks look like wolfeite?+
What minerals are found with wolfeite?+
What kind of rock does wolfeite form in?+
What is wolfeite used for?+
Find wolfeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
