Rock Identifier
Mica (Biotite or Phlogopite variety) (Phyllosilicate (complex mineral formula involving K, Mg, Fe, Al, Si, and O)) — mineral
mineral

Mica (Biotite or Phlogopite variety)

Phyllosilicate (complex mineral formula involving K, Mg, Fe, Al, Si, and O)

Hardness: 2.5–3.0 on Mohs scale; Color: Bronze-gold, brown, or amber; Luster: Pearly to submetallic; Crystal Structure: Monoclinic; Cleavage: Perfect basal cleavage (easily peels into thin, flexible sheets); Specific Gravity: 2.7–3.3.

Hardness
2
Color
Bronze-gold, brown, or amber
Luster
Pearly to submetallic
Identified More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App StoreGoogle Play

Physical properties

Hardness: 2.5–3.0 on Mohs scale; Color: Bronze-gold, brown, or amber; Luster: Pearly to submetallic; Crystal Structure: Monoclinic; Cleavage: Perfect basal cleavage (easily peels into thin, flexible sheets); Specific Gravity: 2.7–3.3.

Formation & geological history

Formed through metamorphic or igneous processes. It is common in pegmatites, schists, and gniesses, typically forming in volcanic environments or at high-pressure metamorphic zones. Can range from hundreds of millions to billions of years old depending on the host rock.

Uses & applications

Used widely in industry as an electrical insulator, in cosmetics (mica shimmer), as a filler in plastics or rubber, and in specialized high-temperature windows for furnaces or kilns.

Geological facts

Mica is famous for its 'books' (large crystals) and was historically used as a glass substitute for lanterns and windows in Russia, earning its name 'Muscovy-glass'. It is highly heat resistant and does not conduct electricity.

Field identification & locations

Identify in the field by its distinct ability to flake apart into paper-thin, transparent, or semi-opaque flexible sheets. It feels slightly greasy or soapy and shows a brilliant 'sparkle' under sunlight. Commonly found in granite outcrops or riverbeds near metamorphic terrain.

More like this

Other mineral specimens

Sandstone (with potential mineral staining/concretions) (Arenite (SiO2 based)) — sedimentary

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary
Epidote (Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)) — metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic
Nephrite Jade (Nephrite) — Mineral/Rock

Nephrite Jade

Nephrite

Mineral/Rock
Banded Gneiss (River Rock/Pebble) (Gneiss (specifically a banded variety often found as a river rock)) — Metamorphic Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock
Green Apatite on Albite (Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]) — mineral

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral
Epidote (Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)) — mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral