mineral

Tumbled jasper or chalcedony

Microcrystalline quartz (SiO₂), probably iron-stained jasper/chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque to weakly translucent, orange-brown, cream, and gray with a waxy to dull luster. It has a cryptocrystalline quartz structure, no obvious cleavage, and typically fractures conchoidally; the rounded shape is from tumbling.

Identified August 13, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich material formed by precipitation from groundwater or volcanic-related fluids, with iron oxides producing the brown-orange coloration. The exact geological age cannot be determined from the photograph; jasper and chalcedony occur in many ages and settings.

Uses & applications

Used as a lapidary stone for cabochons, beads, carvings, and tumbled specimens; it has little industrial value in this form.

Geological facts

Jasper is an opaque variety of microcrystalline quartz, while chalcedony is commonly translucent; many specimens are transitional or marketed under trade names such as “picture jasper” or “ocean jasper.”

Field identification & locations

Commonly found in volcanic terrains, sedimentary silica deposits, and alluvial gravels worldwide. A scratch test against glass, lack of cleavage, and resistance to a steel blade support quartz; exact identification may require a streak, specific-gravity, or microscope test.