Triphylite is a phosphate mineral primarily found in lithium-rich granite pegmatites. It is often identified by its characteristic blue-green to grayish-blue color, though it readily alters to dark brown or black manganese-iron oxides when exposed to air.
Is this triphylite?
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 triphylite with a known reference. Triphylite sits at Mohs 4-4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Triphylite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Triphylite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green, grayish-blue, brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: short prismatic crystals, massive, granular.
Often confused with
Triphylite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside triphylite
Minerals reported to co-occur with triphylite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- LiFePO₄
- Mohs hardness
- 4-4.5
- Density
- 3.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Short Prismatic Crystals, Massive, Granular
- Cleavage
- Perfect On {001}, Good On {010}
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Granite Pegmatites
- Typical price
- $20-150 for thumbnail to small cabinet specimens
Where rockhounds find triphylite
1 mapped spotsClassic worldwide localities
- Hagendorf, Germany
- Keystone, South Dakota, USA
- Newry, Maine, USA
- Norrö, Sweden
- Brazil
Field-hunting tip
Look in granite pegmatites country, the host setting where triphylite typically forms. If you start seeing quartz, albite, beryl in float, you are in the right ground. Field specimens usually show a short prismatic crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wisconsin. Start trip planning there.
Common questions
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Find triphylite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
