RocksdayLepidolite vs Muscovite
How to tell them apart
A lilac, lithium-bearing mica that forms sparkly scaly masses in pegmatites.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Light-colored mica that peels into paper-thin, transparent and flexible sheets. Its flakes are what make many rocks glitter.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Key differences
- Muscovite is colorless to silvery.
Side by side
| Property | Lepidolite | Muscovite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 2.5–3 | 2–2.5 |
| Luster | Pearly | Vitreous to pearly |
| Streak | White | White |
| Colors | Purple, Pink, Gray | Clear, Silver, Brown |
| Crystal system | Monoclinic | Monoclinic |
| Specific gravity | 2.8–2.9 | 2.76–2.88 |
| Formula | K(Li,Al)₃(Al,Si,Rb)₄O₁₀(F,OH)₂ | KAl₂(AlSi₃O₁₀)(OH)₂ |
| Found in | Minas Gerais, Brazil; Madagascar | Pegmatites of North Carolina; New Hampshire |
Properties that are the same for both are grayed out.
How to identify lepidolite
- Lilac to purple, glittering scaly flakes.
- Peels into thin flexible sheets.
- Soft — a fingernail almost scratches it.
Crystal system: Monoclinic
Full Lepidolite guide →How to identify muscovite
- Peels into thin sheets that spring back when bent.
- Transparent to silvery and sparkly.
- Soft — scratched by a fingernail across the sheets.
- Stacked 'books' of sheets in pegmatites.
Crystal system: Monoclinic
Full Muscovite guide →More comparisons
Could you tell them apart from a blurry close-up?
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