metamorphic

Mica-rich metamorphic rock, likely mica schist

Muscovite–biotite schist, possibly with garnet and quartz

AI-generated identification · may be incorrect

Coarse, foliated texture with silvery reflective mica, gray quartz-rich areas, and reddish-brown spots likely garnet or weathered biotite. Micas have Mohs hardness 2–3; quartz is 7 and garnet commonly 6.5–7.5; cleavage is strong in mica and absent in quartz.

Identified September 22, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when shale or another clay-rich sediment was subjected to elevated pressure and temperature during regional metamorphism, commonly during mountain building. The specimen’s exact geological age cannot be determined from the photograph.

Uses & applications

Used locally as decorative stone, aggregate, or educational material; attractive mica schist and garnet-bearing pieces are collected, though it is generally unsuitable for high-quality construction stone because foliation causes splitting.

Geological facts

The glitter comes from aligned mica flakes reflecting light. Reddish rounded grains may be almandine garnet, but confirmation requires a hand lens or testing.

Field identification & locations

Look for planar foliation, glittering mica layers, and easy splitting along schistosity; a streak, hardness, and acid test would help separate it from gneiss or altered granite. Common in metamorphic mountain belts worldwide, including India, Brazil, the Alps, and Appalachians.