sedimentary

Mookaite Jasper

Radiolarite (Silicon Dioxide, SiO2)

Hardness: 6.5-7.0 (Mohs scale); Color: Red, yellow, cream, and purple; Luster: Vitreous to greasy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9.

Hardness: 6
Color: Red, yellow, cream, and purple
Luster: Vitreous to greasy

Identified May 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the skeletal remains of radiolaria (microscopic marine organisms) deposited in shallow sea beds, which were then silicified through groundwater activity during the Cretaceous period (approx. 66-145 million years ago).

Uses & applications

Primarily used for lapidary work, including cabochons, beads, and sculpture. It is highly valued as a gemstone for jewelry and by mineral collectors for its vibrant patterns.

Geological facts

Mookaite is found specifically in the Mooka Creek area of Western Australia. The name 'Mooka' is derived from a local Aboriginal word meaning 'running waters'. It is technically a silicified radiolarite.

Field identification & locations

Identify in the field by its distinct earthy color palette (mustard yellows and deep reds) and smooth, glass-like fracture. It is exclusively sourced from the Windalia Radiolarite formation in Western Australia.

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