mineral

Weathered quartz-rich cobble, possibly milky quartz with iron staining

Quartz (SiO₂), likely with iron-oxide/hydroxide coatings and minor host-rock inclusions

AI-generated identification · may be incorrect

White to tan-brown, opaque to translucent patches, vitreous-to-waxy luster, massive rather than visibly crystalline, and irregular conchoidal fracture; quartz hardness is Mohs 7, with no cleavage and specific gravity about 2.65.

Identified August 11, 2026More mineral →

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At a glance

Common name: Weathered quartz-rich cobble, possibly milky quartz with iron staining
Scientific name: Quartz (SiO₂), likely with iron-oxide/hydroxide coatings and minor host-rock inclusions
Category: mineral
Identified: August 11, 2026
Method: Standard

AI Estimated Value

About $5-$30 as a common field specimen; $30-$100+ if unusually attractive, translucent, well-polished, or locality-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 in a hydrothermal quartz vein or quartz-rich metamorphic rock, then rounded and surface-stained by weathering and stream or glacial transport. The original quartz may be hundreds of millions to billions of years old, depending on locality.

Uses & applications

Mostly a collector or lapidary specimen; sound pieces can be polished or cut, while quartz is industrially important for glass, ceramics, electronics, and abrasives.

Geological facts

The yellow-brown coloration is commonly goethite or limonite, produced by oxidation of iron-bearing minerals. Its rounded shape indicates prolonged mechanical abrasion after release from bedrock.

Field identification & locations

Test with a steel knife or glass: quartz should scratch glass and resist a knife. Common in quartz-vein districts, metamorphic terrains, and gravel deposits worldwide; exact identification would benefit from locality data or testing.