sedimentary

Weathered quartz-rich rock, possibly chert or silicified limestone

Microcrystalline quartz (SiO₂), with probable calcite and iron-oxide impurities

AI-generated identification · may be incorrect

Light gray-beige, dull to weakly waxy luster, massive and fine-grained, with rusty orange iron-oxide staining. Likely hardness about 6–7 if chert/silicified material; cleavage absent, fracture irregular to conchoidal, and specific gravity roughly 2.6–2.7.

Identified August 28, 2026More sedimentary →

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At a glance

Common name: Weathered quartz-rich rock, possibly chert or silicified limestone
Scientific name: Microcrystalline quartz (SiO₂), with probable calcite and iron-oxide impurities
Category: sedimentary
Identified: August 28, 2026
Method: Standard

AI Estimated Value

About $1–$10 as an ordinary hand specimen; potentially $10–$30 if provenance, pattern, or lapidary quality is notable.

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

Probably formed as siliceous sediment or limestone later replaced by silica, followed by surface weathering and iron staining. Its exact geological age cannot be determined from the photograph.

Uses & applications

Common chert is used locally for aggregate, road material, and historically tools; attractive pieces may be collected as lapidary rough. This specimen appears ordinary and has little jewelry value.

Geological facts

The blocky shape and fine texture are consistent with chert, silicified limestone, or another weathered microcrystalline siliceous rock. Orange patches commonly represent limonite or hematite.

Field identification & locations

Test with a steel file or glass: a true quartz-rich specimen should scratch glass, whereas calcitic limestone will not. Vinegar or dilute hydrochloric acid may fizz on exposed calcite; common sources include sedimentary basins and limestone terrains.