metamorphic

Weathered schistose metamorphic rock

Likely mica schist or phyllitic schist; composition commonly quartz, muscovite/biotite, and feldspar

AI-generated identification · may be incorrect

Gray-brown, foliated, strongly fractured rock with a dull to subtly silky luster and visible planar cleavage. Typical hardness is about 2–4 for mica-rich surfaces, with quartz-rich grains reaching 7; density is roughly 2.6–2.8 g/cm³.

Identified September 18, 2026More metamorphic →

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At a glance

Common name: Weathered schistose metamorphic rock
Scientific name: Likely mica schist or phyllitic schist; composition commonly quartz, muscovite/biotite, and feldspar
Category: metamorphic
Identified: September 18, 2026
Method: Standard

AI Estimated Value

As an ordinary outcrop specimen, usually $0–$10; attractive hand specimens or polished pieces may sell for about $10–$50.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when shale or another fine-grained sediment was subjected to regional metamorphism, producing aligned mica and pervasive foliation. Its exact geological age cannot be determined from the image and depends on locality.

Uses & applications

Used locally as crushed aggregate, road material, building stone, and decorative landscaping rock; attractive slabs may be used for architectural stone, though pronounced foliation limits durability.

Geological facts

The layered appearance reflects mineral alignment rather than original sedimentary bedding. Weathering preferentially loosens mica-rich planes, creating the flaky, irregular surface visible here.

Field identification & locations

Identify it by planar foliation, easy splitting along mica-rich surfaces, and a sparkly or silky sheen when freshly broken; distinguish it from slate by its coarser texture and stronger visible mineral grains. Common in regional metamorphic belts worldwide.