mineral

Quartz-rich iron-stained nodule

Microcrystalline quartz (SiO₂), possibly chalcedony with limonite/goethite staining

AI-generated identification · may be incorrect

Gray, rounded, waxy to dull luster with a granular pale-gold iron-oxide patch; likely hardness about 6.5–7 Mohs, no obvious cleavage, conchoidal fracture, and specific gravity near 2.6. The surface appears naturally weathered or lightly polished.

Identified August 27, 2026More mineral →

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At a glance

Common name: Quartz-rich iron-stained nodule
Scientific name: Microcrystalline quartz (SiO₂), possibly chalcedony with limonite/goethite staining
Category: mineral
Identified: August 27, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a common hand specimen; roughly $20–$75 if unusually attractive, locality-documented, or confirmed as a rarer mineral association.

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 silica-rich groundwater filled a cavity or replaced host rock, later acquiring brown-yellow limonite/goethite staining from oxidation. Exact age and locality cannot be determined from the photograph; such nodules occur in sedimentary and volcanic terrains.

Uses & applications

Primarily a collecting specimen; quartz/chalcedony is used in abrasives, glass, electronics, and ornamental stone, while iron oxides provide pigment. The pictured piece has little commercial value unless its locality or internal pattern is notable.

Geological facts

The metallic-looking golden area is more likely iron oxide or mica than native gold. A steel file should barely scratch quartz, while quartz will scratch ordinary glass.

Field identification & locations

Commonly found as rounded nodules in weathered volcanic rocks, limestone, gravels, and silica-rich veins. Confirm with a hardness test, streak test, magnification, and—if valuable—specific-gravity or elemental analysis.