Strunzite is a rare phosphate mineral typically found as radiating clusters of delicate yellow or brown needles. It forms as a secondary mineral during the alteration of primary triphylite in granitic pegmatites. Collectors prize it for its fragile, aesthetic crystal sprays, often found tucked into vugs within phosphate-bearing ore.
Is this strunzite?
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 strunzite with a known reference. Strunzite 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. Strunzite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Strunzite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-brown, brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: acicular or radiating bundles of needle-like crystals.
Often confused with
Strunzite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside strunzite
Minerals reported to co-occur with strunzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn²⁺Fe³⁺₂(PO₄)₂(OH)₂·6H₂O
- Mohs hardness
- 3.5-4
- Density
- 2.54 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Acicular or Radiating Bundles of Needle-like Crystals
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate-rich Granite Pegmatites
- Typical price
- $20-150 thumbnail specimens
Where rockhounds find strunzite
Classic worldwide localities
- Hagendorf, Bavaria, Germany
- Tip Top mine, South Dakota, USA
- Mangualde, Portugal
Field-hunting tip
Look in phosphate-rich granite pegmatites country — that is the host setting where strunzite typically forms. If you start seeing triphylite, rockbridgeite, strengite in float, you are in the right ground. Field specimens usually show a acicular or radiating bundles of needle-like crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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How much is strunzite worth?+
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Find strunzite on the map
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