Mookaite
Silicified radiolarite (SiO2-rich chalcedony/opal)
A vivid Australian jasper-like silica stone in earthy reds, yellows, and purples, formed from silicified radiolarian sediment.
- Mohs hardness
- 6.5-7
- Color
- Cream, yellow, mustard, red, burgundy, purple
- Type
- mineral
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Overview
Mookaite (also spelled mookite) is a richly colored Australian silica rock, marketed as a jasper, displaying bold swirls of cream, yellow, mustard, scarlet, maroon, and plum.
Geologically it is a silicified radiolarite: an originally soft sediment built from the silica skeletons of microscopic marine organisms called radiolaria, later hardened into dense chalcedony and opaline silica.
It is found only at Mooka Station along Mooka Creek in the Kennedy Range of Western Australia, which gives the stone its name.
Formation & geology
Mookaite formed from the Windalia Radiolarite, a Cretaceous marine deposit rich in the siliceous skeletons of radiolaria. Over time, silica-bearing groundwater cemented and replaced the sediment, hardening it into a tough cryptocrystalline silica rock.
The vivid reds, yellows, and purples come from varying amounts and oxidation states of iron oxides (such as hematite and goethite) percolating through the rock.
Its only commercial source is the Mooka Creek area of the Kennedy Range in Western Australia, making it a regionally distinctive Australian gemstone.
How to identify it
Look for strong earthy colors, often mixed in a single piece, with mustard yellow, deep red, and purple being most characteristic. Hardness is about 6.5-7, scratching glass. It takes a high polish and has a waxy to vitreous luster.
It is opaque with a white streak and breaks with a conchoidal fracture like other chalcedony.
Look-alikes: Other jaspers (such as red jasper or ocean jasper) and bloodstone are similar silica rocks; mookaite's distinctive multicolor mustard-and-burgundy palette and Australian origin help identify it. Unlike marble or softer stones, it will not scratch with a knife.
Uses & significance
Mookaite is a popular lapidary stone cut into cabochons, beads, tumbled stones, spheres, and carvings. Its bold colors and ability to take a glassy polish make it a favorite in handmade jewelry.
It has no major industrial use but is valued by collectors and crafters for its uniquely Australian character.
In metaphysical practice it is described as a grounding, vitalizing stone connected to the earth and to physical well-being, claims that are spiritual rather than scientifically established.
Frequently asked questions
Is mookaite a jasper?
It is commonly sold as a jasper, but technically it is a silicified radiolarite, a silica rock formed from the skeletons of marine radiolaria.
Where does mookaite come from?
Only from Mooka Creek and Mooka Station in the Kennedy Range of Western Australia, which is the source of its name.
What gives mookaite its colors?
Iron oxides in different concentrations and oxidation states produce its yellows, reds, and purples.
Is mookaite durable enough for jewelry?
Yes. At about 6.5-7 on the Mohs scale it is durable and polishes well, suitable for pendants, beads, and cabochons.
Mookaite guides
In-depth guides for identifying, valuing, and understanding Mookaite.
Mookaite identified by the community
Real specimens identified with Rock Identifier.
