"Mookaite"

Item Description

According to mindat.org, "The term 'Mookaite' is an unofficial, locally coined name for a silicified porcelanite which forms in the weathering profile of a geological formation known as Windalia Radiolarite (WR), a Lower Cretaceous siltstone that outcrops over much of the Carnarvon Basin in Western Australia. Mookaite is variously, and incorrectly, described as chert, opalite, chalcedony or combinations of the three. From a strictly geological perspective however, Mookaite is best defined as a silicified type of WR whose silification is opaline to chalcedonic." For reference, Porcelanite is defined as "a rock, semi-vitrified clay or shale, somewhat resembling jasper, composed of mullite and other high-temperature silicate and oxide minerals". This stone is an attractive "Mookaite" stone with cream, brown and soft golden hues and a "Cushion Cabochon" cut. One of the few stones of this material that I have offered in the auctions.