sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness (Mohs): 6.5-7. Color: Reddish-pink, brown, and tan. Luster: Dull to vitreous (waxy on fresh surfaces). Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.91.

Color: Reddish-pink, brown, and tan
Luster: Dull to vitreous (waxy on fresh surfaces)

Identified June 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the silicification of fine-grained sedimentary materials such as volcanic ash or mud. This specimen shows a weathered outer cortex with a microcrystalline quartz core that was enriched with iron oxides over millions of years.

Uses & applications

Commonly used in jewelry (cabochons, beads), decorative lapidary arts, and stone healing practices. Due to its hardness, it is also highly valued as a tumbling material for collectors.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone. It has been used since antiquity for royal seals and amulets because of its durability and varied patterns.

Field identification & locations

Identify in the field by its hardness (will scratch glass), opaque nature, and conchoidal (shell-like) fracture patterns. Frequently found in riverbeds and coastal areas as rounded pebbles with a distinctive 'rind' or skin.