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, 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
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
