sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Brown, red, green with banding; Luster: Vitreous to waxy (especially when wet); Structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.

Hardness: 6
Color: Brown, red, green with banding
Luster: Vitreous to waxy (especially when wet)

Identified July 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica in fine-grained sedimentary rock or volcanic ash. The brown and red hues indicate iron oxide (hematite or goethite) inclusions. Often dates back millions of years to the Paleozoic or Mesozoic eras.

Uses & applications

Commonly used for lapidary work including cabochons, beads, and tumbled stones. Historically used for tools (due to conchoidal fracture) and as a decorative building material.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone. It was prized in the ancient world for its supposed protective qualities and ability to bring rain.

Field identification & locations

Identify in the field by its hardness (will scratch glass), smooth texture, and opaque nature. Often found in riverbeds or coastal areas where water erosion has smoothed the exterior. This specimen shows distinct banding/stratification.