Polished fossil Oncolite. ONC110 Orbicular Granite Pilbara region of Western Australia

Pilbara region of Western Australia

Dimensions at widest points approximately 160 mm x 90 mm x 50 mm thick

100 mm x 90 mm x 15 mm thick

60 mm x 50 mm  x 25 mm

Weighs 883 grams

Polished fossil Oncolite. ONC110 Orbicular Granite Pilbara region of Western AustraliaONC110. Fossil Oncolite polished slab. From the Miocene "Trealla Limestone" north of Carnarvon, Western Australia . Age is approx. 15 million years. Dimensions at widest points approx. 125 mm x 70 mm x 8 mm thick. Weighs 172 grams. Oncolite is a limestone composed largely of oncoidsrounded, coated grains that grow as thin layers of lime mud accumulate around a tiny nucleus (such as a sand grain or shell fragment) under microbial influence. Formed in