sedimentary

Mookaite Jasper

Silicified Radiolarite (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Variegated shades of yellow, red, cream, and brown; Luster: Vitreous to waxy; Structure: Microcrystalline/Cryptocrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6-2.9.

Hardness: 6
Color: Variegated shades of yellow, red, cream, and brown
Luster: Vitreous to waxy

Identified March 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed as a sedimentary rock from the fossilized skeletal remains of radiolaria (microscopic marine organisms) that were later silicified by silica-rich groundwater. Found in the Windalia Radiolarite formation, dating back approximately 145–66 million years (Cretaceous period).

Uses & applications

Primarily used in the jewelry industry for cabochons, beads, and pendants. Also used for ornamental carvings, palm stones, and as a popular specimen for mineral collectors due to its unique color patterns.

Geological facts

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

Field identification & locations

Identify by its characteristic earthy color palette (mustard yellows and deep reds) and its high density and hardness. It is exclusively found in the Kennedy Ranges of Western Australia. Collectors should look for vibrant, multi-colored banding and a high-polish finish.