metamorphic

Weathered quartz-bearing metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica rock; exact classification is uncertain from the photograph

AI-generated identification · may be incorrect

Light gray, rounded, and strongly weathered, with white translucent quartz/feldspar and dark mica or other mafic grains; vitreous to dull luster. Quartz has Mohs hardness 7, while feldspar is about 6; visible foliation appears weak or obscured.

Identified August 19, 2026More metamorphic →

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At a glance

Common name: Weathered quartz-bearing metamorphic rock, likely gneiss or schist
Scientific name: Quartz–feldspar–mica rock; exact classification is uncertain from the photograph
Category: metamorphic
Identified: August 19, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as a common field cobble; perhaps $10–$30 if unusually attractive or locally significant.

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

Likely formed when quartz- and feldspar-rich sediment or igneous rock underwent regional metamorphism, then was eroded into a rounded cobble. Its geological age cannot be determined visually and may range from Precambrian to much younger.

Uses & applications

Ordinary specimens are used as aggregate, riprap, and landscaping stone; attractive polished pieces may be decorative, but this specimen has limited commercial use.

Geological facts

The rounded shape indicates transport by water, ice, or coastal abrasion. Yellow-brown patches are probably iron-oxide weathering, while greenish areas may represent altered mica or chlorite.

Field identification & locations

Look for interlocking quartz/feldspar grains, mica-rich dark streaks, and any planar foliation; a streak, hardness, and acid test would help distinguish it from quartzite, granite, or concrete. Common in glacial deposits, river gravels, and metamorphic terrains.