Zinnwaldite is a lithium-bearing mica that commonly occurs as short, thick tabular crystals or micaceous books. It is most often found in greisens and lithium-rich granite pegmatites, frequently associated with tin and tungsten deposits.
Is this zinnwaldite?
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 zinnwaldite with a known reference. Zinnwaldite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Zinnwaldite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Zinnwaldite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellowish-brown, brown, dark gray, violet.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, micaceous masses.
Often confused with
Zinnwaldite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside zinnwaldite
Minerals reported to co-occur with zinnwaldite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KLiFeAl(AlSi₃)O₁₀(F,OH)₂
- Mohs hardness
- 2.5-3
- Density
- 2.9-3.0 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Micaceous Masses
- Cleavage
- Perfect Basal
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Granite Pegmatites, Greisens
- Typical price
- $10-100 per specimen
Where rockhounds find zinnwaldite
1 mapped spotsClassic worldwide localities
- Zinnwald
- Czech Republic
- Altenberg
- Germany
- Cornwall
- UK
Field-hunting tip
Look in granite pegmatites, greisens country — that is the host setting where zinnwaldite typically forms. If you start seeing cassiterite, topaz, wolframite in float, you are in the right ground. Field specimens usually show a tabular crystals, micaceous masses habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wisconsin — start trip planning there.
Common questions
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Find zinnwaldite on the map
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