mineral

Quartz-rich chalcedony (likely agate or jasper)

Microcrystalline quartz, SiO₂; possibly a quartzite or silicified rock

AI-generated identification · may be incorrect

Cream, white, tan, and brown mottled material with a dull-to-waxy luster and no visible cleavage; quartz hardness is about 7 Mohs, with specific gravity near 2.6. The rounded shape appears naturally water-worn or tumbled.

Identified September 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities or replace existing rock, commonly in volcanic environments; exact age cannot be determined visually. If quartzite, it formed by metamorphism of sandstone.

Uses & applications

Used for lapidary carving, cabochons, beads, polished stones, and ornaments; massive low-grade pieces have little industrial value.

Geological facts

Agate typically shows curved or concentric banding, while jasper is more opaque and uniformly mottled; this specimen lacks enough visible detail for a definitive distinction.

Field identification & locations

Check for translucent edges, waxy luster, conchoidal fracture, and hardness sufficient to scratch ordinary glass; streak is white. Common sources include volcanic terrains in Brazil, Uruguay, Mexico, India, and the western United States.