sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2)
Hardness: 6.5–7 on the Mohs scale. Color: Earthy tones including red, yellow, mustard, purple, and cream. Luster: Vitreous to dull. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific gravity: 2.63–2.65.
- Hardness
- 6
- Luster
- Vitreous to dull
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5–7 on the Mohs scale. Color: Earthy tones including red, yellow, mustard, purple, and cream. Luster: Vitreous to dull. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific gravity: 2.63–2.65.
Formation & geological history
Formed from the fossilized remains of radiolaria (microscopic marine organisms) that settled in shallow sea beds during the Cretaceous period (approx. 145–66 million years ago), which then underwent silicification.
Uses & applications
Primarily used in jewelry making (cabochons and beads), rock tumbling, lapidary arts, and as decorative ornamental stone.
Geological facts
Mookaite is found exclusively in Western Australia at Mooka Station near the Kennedy Ranges. The name 'Mooka' comes from an Aboriginal word meaning 'running waters.' It is technically a biogenic sedimentary rock that has been replaced by silica.
Field identification & locations
Identify by its unique earthy color palette and high polish. In the field, look for opaque, multicolored nodules in the Windalia Radiolarite formation. Collectors value pieces with distinct banding or rare purple hues.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary