mineral

Quartz-rich rock, possibly yellow chalcedony or weathered quartzite

Quartz (SiO₂), likely microcrystalline chalcedony with iron-oxide staining

AI-generated identification · may be incorrect

Whitish to gray material with strong yellow staining and a dull-to-waxy luster; irregular fracture and no obvious cleavage. Quartz has Mohs hardness 7 and specific gravity about 2.65; the yellow color commonly comes from limonite/goethite inclusions.

Identified September 10, 2026More mineral →

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At a glance

Common name: Quartz-rich rock, possibly yellow chalcedony or weathered quartzite
Scientific name: Quartz (SiO₂), likely microcrystalline chalcedony with iron-oxide staining
Category: mineral
Identified: September 10, 2026
Method: Standard

AI Estimated Value

About $1–$15 as a common rough specimen; potentially $20–$50 if it proves to be attractive, polishable chalcedony.

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 from silica-rich fluids or recrystallized quartz, later altered and stained by iron-bearing groundwater. Exact geological age and rock classification cannot be established from the photograph alone.

Uses & applications

Used as an ornamental or lapidary material if it takes a polish; otherwise mainly a common collecting specimen. It is not typically valuable for construction in this small form.

Geological facts

The specimen appears consistent with the note describing a black-, white-, and yellow-colored backyard stone, though the photograph shows mostly yellow-white with gray areas.

Field identification & locations

Test with a steel file: genuine quartz should resist scratching; a streak test is usually white. Acid reaction should be absent, helping distinguish it from calcite; a definitive ID may require hardness, streak, and thin-section or chemical testing.