sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown, tan, or multicolored; Luster: Vitreous to waxy (especially when wet); Structure: Microcrystalline quartz; Cleavage: None, conchoidal fracture.

Hardness: 6
Color: Reddish-brown, tan, or multicolored
Luster: Vitreous to waxy (especially when wet)

Identified April 21, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown, tan, or multicolored; Luster: Vitreous to waxy (especially when wet); Structure: Microcrystalline quartz; Cleavage: None, conchoidal fracture.

Formation & geological history

Formed through the accumulation of fine silica-rich sediment or volcanic ash. Over millions of years, heat and pressure solidify the material into chalcedony, with iron oxides providing the characteristic red or brown coloring.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), interior decoration, and as a popular specimen for crystal collecting and rock tumbling.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Old French word 'jaspre', meaning 'spotted or speckled stone'. It has been used for seals and amulets since ancient Mesopotamian times.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its opaque nature, and the smooth, waxy feel of its surface when water-worn. Common in riverbeds and coastal areas.