Polished fossil Oncolite. ONC109 Polished rock. Dimensions at widest points approximately

Dimensions at widest points approximately 100 mm high x 100 mm x 30 mm thick

Dimensions approximately 85 mm x 75 mm x 12

Dimensions at widest points approximately 100 mm x 90 mm x 50 mm thick

Dimensions at widest points approximately 70 mm x 35 mm x 30 mm thick

TIR146 Tiger Iron rough rock

Polished fossil Oncolite. ONC109 Polished rock. Dimensions at widest points approximatelyONC109. 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. 150 mm x 65 mm x 6. 5 mm thick. Weighs 117 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