metamorphic

Weathered quartz-rich metamorphic rock, likely gneiss or quartzite

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

AI-generated identification · may be incorrect

Hardness about 6–7 Mohs; pale gray, cream, tan, and rusty-orange from iron-oxide weathering, with a granular texture and dull to vitreous luster. Visible dark mica or amphibole-rich patches and possible foliation suggest gneiss rather than pure quartzite.

Identified September 15, 2026More metamorphic →

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At a glance

Common name: Weathered quartz-rich metamorphic rock, likely gneiss or quartzite
Scientific name: Quartz–feldspar–mica metamorphic rock; exact identification is uncertain from the photograph
Category: metamorphic
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $5–$25 as an ordinary hand specimen; $25–$75 if it displays unusually clear foliation, mineral contrast, or locality significance.

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 quartz- and feldspar-bearing sedimentary or igneous rock was subjected to elevated heat and pressure, probably during Precambrian or Paleozoic regional metamorphism; surface oxidation is much younger.

Uses & applications

Suitable varieties may be used as aggregate, road stone, riprap, building stone, or decorative slabs; attractive pieces are collected but this specimen has limited commercial value.

Geological facts

The orange-brown coloration commonly results from limonite or hematite coating fractures and weathered feldspar. A streak, fresh broken surface, and examination for mineral banding would distinguish gneiss from quartzite or weathered granite.

Field identification & locations

Common in ancient continental shields and metamorphic mountain belts worldwide. Look for interlocking quartz and feldspar, dark mica bands, strong hardness, and lack of acid reaction; a steel knife should not easily scratch it.