Brecciated Mookaite

This is another new find from the outback of Western Australia. It occurs near Mooka Station in the Kennedy Ranges about 100 miles inland from the coastal town of Carnarvon. This geologically interesting rock is actually a brecciated radiolarite. Radiolarite or radiolarian chert is a high silica sedimentary rock which may be considered a variety of chert. It is formed as primary deposits and contains radiolarian microfossils. Locally the varicolored opaline to chalcedonic radiolarite is mined and used as a popular stone called Mookaite.

A brecciated variety of Mookaite has been found. It is from the same deposit as normal Mookaite, just a few levels deeper in the ground. The Aussies are calling it “Brecciated Mookaite”. This stone is composed of opaque segments bordered with translucent borders. This creates an interesting puzzle like mosaic of colors that ranges from mustard yellows, creamy whites and tan browns. This Brecciated Mookaite really holds together well and since almost all portions are the same hardness it takes an excellent polish with minimal undercut. As with any brecciated material, there is a possibility of having small voids in the stone. It cuts and polishes nicely and will work for small cabs all the way up to large specimens.