sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2 with iron impurities)
Hardness: 6.5-7 (Mohs); Color: Mixed yellows, reds, creams, and purples; Luster: Vitreous to greasy; Crystal Structure: Trigonal (microcrystalline); Specific Gravity: 2.65
- Hardness
- 6
- Color
- Mixed yellows, reds, creams, and purples
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Mixed yellows, reds, creams, and purples; Luster: Vitreous to greasy; Crystal Structure: Trigonal (microcrystalline); Specific Gravity: 2.65
Formation & geological history
Formed through the silicification of radiolarian oozes (skeletal remains of microscopic marine organisms) in the Windalia Radiolarite formation during the Lower Cretaceous period approximately 120 million years ago.
Uses & applications
Primarily used in lapidary work for jewelry, cabochons, carvings, and as a popular collector's mineral due to its organic patterns and vibrant earth tones.
Geological facts
Mookaite is named after Mooka Creek in Western Australia, which is currently the only place in the world where this specific variety is found. The name 'Mooka' is an Indigenous word meaning 'running waters'.
Field identification & locations
Identify by its characteristic 'smeared' paint-like patterns and presence of high-silica chert-like texture. It occurs primarily in the Kennedy Ranges near Gascoyne Junction, Australia; collectors look for pieces with high contrast between the ochre yellows and deep maroons.
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