Eosphorite typically occurs as attractive, delicate, pinkish-brown prismatic crystals or radial sprays within granitic pegmatites. It is highly sought after by mineral collectors for its sharp crystal morphology and aesthetic associations with other phosphate minerals.
Is this eosphorite?
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 eosphorite with a known reference. Eosphorite 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 to resinous.
- 4Match the color rangeCompare against the expected color range: light pink, yellow brown, light brown, light yellow, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, prismatic, striated.
Often confused with
Eosphorite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside eosphorite
Minerals reported to co-occur with eosphorite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn²⁺AlPO₄(OH)₂·H₂O
- Mohs hardness
- 5
- Density
- 3.06-3.08 g/cm³
- Streak
- White
- Luster
- Vitreous to resinous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, prismatic, striated
- Cleavage
- {100}, poor
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Typically a secondary mineral in some phosphate-bearing granite pegmatites
Where rockhounds find eosphorite
Classic worldwide localities
- Branchville, Fairfield Co., Connecticut, USA
- A number of places around Newry, in the Red Hill and Black Mountain quarries, Rumford, Oxford Co., Maine, USA
- Hugo mine, 1.5 km south of Keystone, Pennington Co., South Dakota, USA
- Foote mine, near Kings Mountain, Cleveland Co., North Carolina, USA
- Hagendorf, Bavaria, and on the Greifensteine, near Ehrenfriedersdorf, Saxony, Germany
- Viitaniemi pegmatite, Eräjärvi, Finland
Field-hunting tip
Where it forms: Typically a secondary mineral in some phosphate-bearing granite pegmatites. If you start seeing rhodochrosite, lithiophilite, triploidite in float, you are in the right ground. Typical habit: massive, prismatic, striated. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify eosphorite?+
Where is eosphorite found?+
What rocks look like eosphorite?+
What minerals are found with eosphorite?+
What kind of rock does eosphorite form in?+
What is eosphorite used for?+
Find eosphorite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
