Mookaite jasper, also known as mookite, mookalite, mookerite, moakite, moukalite and moukaite. However, mookaite is considered the correct spelling and is named after the local area it comes from, Mooka Creek in the Kennedy Ranges near Gascoyne Junction which is about 100 miles inland from the coastal town of Carnarvon in Western Australia.
Mookaite is found only in Australia and is actually a fossiliferous sedimentary rock & it is reasonably common to find cavities left by decomposed belemnite casts or in some rare cases , impressions of ammonites. (Windalia Radiolarite) Microscopic examination shows this rock consists of the remains of tiny organisms known as radiolaria that have an unusual skeletal structure of opaline silica. Billions of these little critters were deposited as sediment in the shallow areas of ancient sea beds. When the seas retreated, these sediments were cemented into solid rock by silica carried in groundwater. The type and degree of silicification varies from place to place, forming opalite, chert and chalcedony.
It has been found in many very bright colors, reds, purples, tan, snow white, ivory white, pinks and many other shades. Sometimes but not often it will have black dendrites and in the hands of a careful lapidary the cabochons can be stunning especially if you get very lucky and run into a nice dendrite tree. The more scenic the more these cabochons will bring. A hundred dollars is common for a nice dendritic stone.