mineral

Small tumbled jasper or chert pebbles

Microcrystalline quartz (SiO₂), likely iron-oxide-bearing jasper/chalcedony

AI-generated identification · may be incorrect

Opaque to translucent brown, red, and cream pieces with waxy to dull luster and no visible cleavage; quartz hardness is about Mohs 7, with specific gravity near 2.6. Their rounded surfaces indicate tumbling or natural abrasion.

Identified September 2, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich fluids replaced or cemented fine sediments, with iron and other impurities producing the red-brown colors; ages vary widely by locality, commonly Paleozoic to Cenozoic. The specimens appear polished/tumbled rather than freshly broken.

Uses & applications

Used for inexpensive cabochons, beads, carvings, lapidary work, and decorative stone; common tumbled pieces usually have modest collector value.

Geological facts

Jasper is an opaque variety of chalcedony, while chert may be translucent or opaque and can look similar. Color patterns result mainly from iron oxides, manganese, and included host-rock fragments.

Field identification & locations

Identify by testing for glass-scratching hardness, observing the smooth waxy texture, and distinguishing it from softer dyed materials; jasper and chert occur worldwide in volcanic and sedimentary terrains, including the western United States, Brazil, India, and Madagascar.