sedimentary

Mookaite Jasper

Silicified Radiolarite (SiO2)

Hardness: 6.5-7.0 (Mohs); Color: Mixed yellow, cream, tan, and reddish-brown; Luster: Vitreous to greasy (polished); Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.63-2.65

Hardness: 6
Color: Mixed yellow, cream, tan, and reddish-brown
Luster: Vitreous to greasy (polished)

Identified June 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the silicification of radiolarian siltstones, consisting of the skeletal remains of microscopic sea creatures (radiolaria). It is primarily found in the Windalia Radiolarite formation in Western Australia, dating back to the Lower Cretaceous period (approx. 120 million years ago).

Uses & applications

Mainly used as a lapidary material for jewelry (cabochons, beads), decorative carvings, and as a popular collector's specimen due to its unique vibrant colors.

Geological facts

The name 'Mookaite' is derived from Mooka Creek in Western Australia, the only place in the world where this specific stone is found. 'Mooka' is an Aboriginal word meaning 'running waters.'

Field identification & locations

Identify by its distinctive earthy color combinations and porcelain-like texture. Collectors look for high-contrast patterns and lack of visible fractures. It can be found in the Kennedy Ranges near Gascoyne Junction, Australia.