Phosphorrösslerite is a rare hydrous magnesium phosphate mineral typically occurring as fragile, colorless to white blades or radial sprays. It is an secondary mineral found in oxidized zones of ore deposits, often associated with guano-rich environments or phosphate-bearing hydrothermal veins.
Is this phosphorrösslerite?
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 phosphorrösslerite with a known reference. Phosphorrösslerite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Phosphorrösslerite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Phosphorrösslerite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, radial aggregates, crusts.
Often confused with
Phosphorrösslerite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside phosphorrösslerite
Minerals reported to co-occur with phosphorrösslerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgHPO₄·7H₂O
- Mohs hardness
- 2-3
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Radial Aggregates, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Ore Deposits
- Typical price
- $20-100 per specimen
Where rockhounds find phosphorrösslerite
Classic worldwide localities
- Johanngeorgenstadt, Germany
- Jachymov, Czech Republic
- Laurion, Greece
Field-hunting tip
Look in oxidized hydrothermal ore deposits country — that is the host setting where phosphorrösslerite typically forms. If you start seeing newberyite, vivianite, guanine in float, you are in the right ground. Field specimens usually show a bladed crystals, radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.




