Nanpingite is a rare cesium-rich mica typically found as small, platy inclusions or aggregates within highly evolved pegmatites. Because it closely resembles common muscovite, it is often identified primarily through chemical analysis or specialized X-ray diffraction in geological research settings.
Is this nanpingite?
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 nanpingite with a known reference. Nanpingite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on sheets.
- 4Match the color rangeCompare against the expected color range: white, silver white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crystalline, pseudo hexagonal, radial.
Often confused with
Nanpingite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous, pearly on sheets on Nanpingite and pearly to waxy when fine-grained on Polylithionite.
How to tell apart: Luster reads vitreous, pearly on sheets on Nanpingite and pearly to vitreous on Lepidolite.
Often found alongside nanpingite
Minerals reported to co-occur with nanpingite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CsAl₂(Si₃Al)O₁₀(OH)₂
- Mohs hardness
- 2-3
- Density
- 3.11 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous, pearly on sheets
- Transparency
- Transparent in flakes
- Crystal system
- Monoclinic
- Crystal habit
- Crystalline, pseudo hexagonal, radial
- Cleavage
- {001}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In veinlets in the pollucite-rich middle zone of a muscovite-albite-spodumene pegmatite
Where rockhounds find nanpingite
Classic worldwide localities
- Nanping area, Fukien Province, China (type locality)
Field-hunting tip
Where it forms: In veinlets in the pollucite-rich middle zone of a muscovite-albite-spodumene pegmatite. If you start seeing montebrasite, quartz, apatite in float, you are in the right ground. Typical habit: crystalline, pseudo hexagonal, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify nanpingite?+
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What rocks look like nanpingite?+
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Find nanpingite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
