Phosphophyllite is a highly prized phosphate mineral, famous among collectors for its exquisite pale green color and complex twinning habits. Due to its extreme rarity and fragility, it is rarely found in jewelry and is almost exclusively sought by high-end mineral collectors.
Is this phosphophyllite?
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 phosphophyllite with a known reference. Phosphophyllite sits at Mohs 3-3.5, 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.
- 4Match the color rangeCompare against the expected color range: colorless, blue green, light green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: druse.
Often confused with
Phosphophyllite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside phosphophyllite
Minerals reported to co-occur with phosphophyllite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₂Fe(PO₄)₂·4H₂O
- Mohs hardness
- 3-3.5
- Density
- 3.08-3.13 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Druse
- Cleavage
- On {100}, perfect; on {010}, {102}, distinct
- Rarity
- Rare
- Uses
- Collector, Gemstone
- Host rock
- Typically a secondary mineral in zoned complex granite pegmatites, an alteration product of sphalerite and Fe–Mn phosphates; in hydrothermal vein deposits
Where rockhounds find phosphophyllite
Classic worldwide localities
- Palermo #1 mine, near North Groton, Grafton Co., New Hampshire, USA
- Red Hill, Rumford, and from Newry, Oxford Co., Maine, USA
- Hagendorf, Bavaria, Germany
- Přibyslavice, Czech Republic
- Norrö pegmatite, on Rånö Island, Sweden
- Unificada mine, Cerro Rico, and from the Siglo XX mine, Llallagua, Potosí, Bolivia
Field-hunting tip
Where it forms: Typically a secondary mineral in zoned complex granite pegmatites, an alteration product of sphalerite and Fe–Mn phosphates; in hydrothermal vein deposits. If you start seeing triplite, triphylite, sphalerite in float, you are in the right ground. Typical habit: druse. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify phosphophyllite?+
Where is phosphophyllite found?+
What rocks look like phosphophyllite?+
What minerals are found with phosphophyllite?+
What kind of rock does phosphophyllite form in?+
What is phosphophyllite used for?+
Find phosphophyllite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
