Steinmetzite is a rare phosphate mineral typically found as small, thin platy crystals in the oxidation zones of phosphate-rich granite pegmatites. It is often discovered as an alteration product of other phosphate minerals like phosphophyllite, and collectors should look for its distinctive triclinic bladed habit.
Is this steinmetzite?
3-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 steinmetzite with a known reference. Steinmetzite sits at Mohs 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.
- 3Look at form & habitCrystal system: triclinic. Typical habit: platy crystals.
Often confused with
Steinmetzite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside steinmetzite
Minerals reported to co-occur with steinmetzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₂Fe(PO₄)₂(OH)(H₂O)₃
- Mohs hardness
- 3.5
- Density
- 2.96 g/cm³
- Streak
- White
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Platy crystals
- Cleavage
- Good on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From a highly oxidized zone of a granitic pegmatite, formed by alteration and replacement of phosphophyllite by oxidation of iron and some replacement of zinc by iron
Where rockhounds find steinmetzite
Classic worldwide localities
- Hagendorf Süd pegmatite, Cornelia mine, Oberpfalz, Bavaria, Germany
Field-hunting tip
Where it forms: From a highly oxidized zone of a granitic pegmatite, formed by alteration and replacement of phosphophyllite by oxidation of iron and some replacement of zinc by iron. If you start seeing albite, apatite, chalcophanite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify steinmetzite?+
Where is steinmetzite found?+
What rocks look like steinmetzite?+
What minerals are found with steinmetzite?+
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Find steinmetzite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
