metamorphic

Banded metamorphic rock, likely gneiss

Banded quartzofeldspathic gneiss (probable paragneiss or orthogneiss)

AI-generated identification · may be incorrect

Coarse-grained, strongly foliated rock with alternating pale quartz/feldspar-rich bands and dark biotite- or amphibole-rich layers. Typical hardness is about 6–7; vitreous to pearly luster, granular crystal texture, and poor cleavage overall, though mica flakes cleave readily.

Identified August 20, 2026More metamorphic →

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Physical properties

Formation & geological history

Produced by high-grade regional metamorphism that segregated minerals into compositional bands, commonly from granite or sedimentary protoliths. Exact age cannot be determined visually; gneiss ranges from Archean to younger mountain-building events.

Uses & applications

Used locally as dimension stone, facing stone, paving, riprap, and aggregate; attractive slabs may be used decoratively, though strong foliation can reduce durability.

Geological facts

The image shows an exposed, intensely banded outcrop being examined with a rock hammer; the pale veins or bands are likely quartz and feldspar rather than sedimentary bedding.

Field identification & locations

Identify it by alternating light and dark mineral bands, visible mica, and a crystalline texture; distinguish it from schist by its thicker, less micaceous bands and more massive structure. Common worldwide in ancient continental shields and metamorphic mountain belts.