sedimentary

Chert (Mookaite style)

Silicon Dioxide (SiO2) with various inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Variegated mustard yellow, burgundy, and brown, Luster: Dull to waxy, Crystal Structure: Cryptocrystalline, Fracture: Conchoidal

Hardness: 6

Identified July 2, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Variegated mustard yellow, burgundy, and brown, Luster: Dull to waxy, Crystal Structure: Cryptocrystalline, Fracture: Conchoidal

Formation & geological history

Formed from the skeletal remains of radiolaria (microscopic marine organisms) deposited in shallow seabed environments, later undergoing silicification. This specific coloration is characteristic of the Windalia Radiolarite in Western Australia.

Uses & applications

Primarily used as a lapidary material for jewelry, cabochons, and decorative carvings; historically used by indigenous people for stone tools.

Geological facts

The term 'Mookaite' comes from Mooka Creek in Western Australia. It is a silicified radiolarite that is highly sought after by collectors for its vibrant, clay-like appearance.

Field identification & locations

Identify by its waxy texture, shark-like conchoidal fractures, and distinct color bands. Often found in scree slopes or creek beds in specific Australian localities.