metamorphic

Quartz-rich mica schist (probable)

Mica–quartz schist; mainly quartz (SiO₂) with muscovite/biotite mica and possibly feldspar

AI-generated identification · may be incorrect

Coarse, strongly foliated and sparkly, with pale gray quartz-rich bands and dark reflective mica flakes; quartz hardness 7, mica about 2–3, and overall variable hardness. Vitreous quartz luster contrasts with pearly mica; cleavage is excellent in mica and poor in quartz.

Identified September 8, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when a clay-rich sedimentary protolith was regionally metamorphosed under directed pressure and elevated temperature, commonly during mountain building. The specimen likely records Paleozoic or older metamorphism, though age cannot be determined from the photograph.

Uses & applications

Commonly used as decorative stone, aggregate, and occasionally building or landscaping material; attractive pieces are collected, but it is generally not a jewelry gemstone.

Geological facts

The glittering planar flakes and tendency to split along foliation are characteristic of schistosity. Dark flakes may be biotite, while silvery flakes are likely muscovite.

Field identification & locations

Look for aligned mica flakes, wavy foliation, and interlocking quartz lenses; a fresh surface should sparkle strongly. Common in metamorphic mountain belts worldwide, including the Appalachians, New England, Scotland, and the Alps.