Muscovite

Light-colored mica that peels into paper-thin, transparent and flexible sheets. Its flakes are what make many rocks glitter.

Muscovite specimen — Photo: Robert M. Lavinsky, CC BY-SA 3.0, via Wikimedia Commons

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.

Often confused with

Biotite
Biotite is the dark brown-to-black mica.
Compare side by side
Gypsum
Gypsum flakes bend but don't spring back.
Compare side by side

Where it's found

Pegmatites of North Carolina
New Hampshire
Minas Gerais, Brazil
India

Uses

Electrical insulation, and the shimmer in paint and cosmetics.

Rock tumbling

Not suitable for tumbling.

Did you know?

Sheets were used as window panes in Russia — 'Muscovy glass' gave the mineral its name.

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