Polished jasper pebble

Opaque, smoothly polished, reddish-brown, yellow, gray, and cream banding; dull to waxy luster. Mohs hardness 6.5–7, no cleavage, cryptocrystalline quartz structure, specific gravity about 2.5–2.7.

Jasper forms when silica-rich groundwater replaces or fills cavities in volcanic or sedimentary rocks, with iron oxides producing the red and yellow colors. Deposits range from Precambrian to recent, depending on locality.

Used for cabochons, beads, carvings, decorative objects, and inexpensive collectibles; polished pieces commonly have modest value.

The pattern resembles brecciated or orbicular jasper, though the photograph alone cannot determine the precise variety. Jasper is an opaque variety of chalcedony, unlike transparent quartz varieties.

Commonly found in volcanic terrains and silica-rich gravels, including India, Madagascar, Brazil, Australia, and the western United States. Field identification relies on opacity, vivid iron staining, hardness, and a fine, non-granular texture; a glass scratch test can help confirm quartz hardness.