mineral

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Multi-colored with stripes of yellow, brown, and grey; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.91

Hardness: 6
Color: Multi-colored with stripes of yellow, brown, and grey
Luster: Vitreous to waxy

Identified June 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in fissures or volcanic ash beds. This specimen appears to be a river-tumbled pebble, likely from the Holocene age as surface find, but the mineral itself can date back to various geological eras.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), river rock landscaping, and as a popular specimen for amateur rock hounds and tumblers.

Geological facts

Jasper is an opaque variety of chalcedony that owes its color to impurities, usually iron oxides. Because it is highly durable, it was historically used for making cylinder seals and jewelry in ancient civilizations.

Field identification & locations

Identify in the field by its opacity, conchoidal fracture (chip patterns), and extreme hardness—it will scratch glass and metal. Frequently found in riverbeds, glacial tills, and desert pavements.