Polished fossil Oncolite. ONC111 outback jasper OG172 Polished orbicular granite with

OG172   Polished orbicular granite with natural rough back

cut and polished on one side at right angles to crystal growth

Dimensions at widest points approximately 75 mm

60 mm x 25 mm  x 18 mm

Weight is 865 grams

Polished fossil Oncolite. ONC111 outback jasper OG172 Polished orbicular granite withONC111. 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. 140 mm x 100 mm x 6. 5 mm thick. Weighs 204 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