Phosphosiderite is a rare phosphate mineral prized by collectors for its vivid magenta to violet color. It is most commonly found in massive or nodular habits and is often polished for cabochons due to its attractive, soft appearance.
Is this phosphosiderite?
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 phosphosiderite with a known reference. Phosphosiderite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Phosphosiderite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Phosphosiderite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: pink, violet, magenta, reddish-purple.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, nodular, botryoidal, occasionally small tabular crystals.
Often confused with
Phosphosiderite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside phosphosiderite
Minerals reported to co-occur with phosphosiderite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FePO₄·2H₂O
- Mohs hardness
- 3.5-4
- Density
- 2.76 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, Nodular, Botryoidal, Occasionally Small Tabular Crystals
- Cleavage
- Distinct
- Rarity
- Uncommon
- Uses
- Collector, Lapidary
- Host rock
- Hydrothermal Veins, Granite Pegmatites
- Typical price
- $10-100 depending on specimen quality and size
Where rockhounds find phosphosiderite
Classic worldwide localities
- Argentina
- Germany
- United States
- Portugal
- Brazil
Field-hunting tip
Look in hydrothermal veins, granite pegmatites country — that is the host setting where phosphosiderite typically forms. If you start seeing strengite, vivianite, triplite in float, you are in the right ground. Field specimens usually show a massive, nodular, botryoidal, occasionally small tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify phosphosiderite?+
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How much is phosphosiderite worth?+
What rocks look like phosphosiderite?+
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Find phosphosiderite on the map
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