sedimentary

Weathered quartz-rich rock, likely arkose or quartzite

Quartz-dominant siliciclastic rock; probable arkose (quartz + feldspar), possibly weakly metamorphosed quartzite

AI-generated identification · may be incorrect

Hardness about 6–7 Mohs; tan, cream, and rusty-brown, with a granular texture, vitreous to dull luster, and no obvious cleavage. The visible grains and iron-oxide staining suggest quartz and altered feldspar in a cemented matrix.

Identified September 6, 2026More sedimentary →

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At a glance

Common name: Weathered quartz-rich rock, likely arkose or quartzite
Scientific name: Quartz-dominant siliciclastic rock; probable arkose (quartz + feldspar), possibly weakly metamorphosed quartzite
Category: sedimentary
Identified: September 6, 2026
Method: Standard

AI Estimated Value

About $5–$20 as an ordinary hand specimen; more if locality, provenance, or unusual mineralization is documented.

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 from sand deposited in a continental or alluvial environment, then compacted and cemented; iron oxidation produced the brown coloration. Exact age and classification require a fresh surface, hand lens, and hardness/streak tests.

Uses & applications

Common varieties are used as aggregate, building stone, and occasionally decorative material; this specimen has mainly educational or modest collecting value.

Geological facts

Angular, visible grains favor arkose or poorly sorted sandstone; a very hard, interlocking texture would instead support quartzite. Feldspar alteration may account for the pale, crumbly patches.

Field identification & locations

Common in continental sedimentary basins and metamorphic belts worldwide. Test whether grains scratch glass and inspect a broken surface: gritty cemented grains indicate sandstone/arkose, while fused interlocking grains indicate quartzite.