mineral

Tumbled jasper/chalcedony pebble

Microcrystalline quartz (SiO₂), likely jasper with chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; opaque cream, pink, orange, and brown coloration with a waxy to dull luster. Quartz has trigonal crystal structure, but the microcrystalline texture obscures individual crystals; cleavage is absent and fracture is conchoidal.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities or replace volcanic sediment, later becoming iron-stained jasper and chalcedony. The specimen appears naturally worn or tumbled; its precise geological age and source cannot be determined from the image.

Uses & applications

Used for beads, cabochons, carvings, decorative objects, and lapidary practice; attractive patterned pieces are collected as gemstones.

Geological facts

Jasper is an opaque variety of quartz, while chalcedony is typically translucent; many commercial pieces contain both textures. Iron oxides commonly produce the red, orange, and brown colors.

Field identification & locations

Identify by its very high hardness, lack of cleavage, dense feel, and inability to scratch with a steel knife; it should scratch ordinary glass. Common sources include volcanic terrains in Brazil, Madagascar, India, Mexico, and the western United States.