Polished fossil Oncolite slab. ONC113 Jasper Dimensions at widest points approximately

Dimensions at widest points approximately 195 mm x 100 mm x 60 mm thick

Pilbara region

Dimensions at widest points approximately 190 mm x 130 mm x 30 mm thick

Dimensions at widest points approximately 140 mm x 100 mm x 70 mm thick

polymictic

Polished fossil Oncolite slab. ONC113 Jasper Dimensions at widest points approximatelyONC113. 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. 165 mm x 160 mm x 9 mm thick. Weighs 449 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