mineral

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely opaque chalcedony/jasper

AI-generated identification · may be incorrect

Smooth, rounded, polished surface; mottled brown, olive-green, gray, and cream colors with a waxy to vitreous luster. Hardness is approximately 6.5–7 Mohs; no visible cleavage; specific gravity about 2.6.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities or replace sedimentary material, commonly producing microcrystalline quartz with iron-oxide and clay inclusions. The specimen has been human-tumbled and polished; its precise geological age and source cannot be determined from the image.

Uses & applications

Used as an inexpensive ornamental stone, bead, cabochon, worry stone, and lapidary material; occasionally used decoratively in mosaics and small carvings.

Geological facts

Jasper is an opaque variety of chalcedony, while chert is a closely related microcrystalline quartz rock; color zoning and translucency can overlap between them.

Field identification & locations

Identify by its glassy/waxy polish, very high hardness, and resistance to scratching by a steel knife; it should not fizz in dilute hydrochloric acid. Common sources include the western United States, Mexico, Brazil, India, and Australia.