Polished fossil Oncolite slab. ONC113 Tiger Eye 120 mm x 70 mm

120 mm x 70 mm x 25 mm thick

pale blue cleavelandite

OJ172  A slab

All reasonably uniform in size (roughly 20 - 30 mm diameter}

55 mm x 30 mm  x 35 mm

Polished fossil Oncolite slab. ONC113 Tiger Eye 120 mm x 70 mmONC113. 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