Polished fossil Oncolite slab. ONC112 microbialite 55 mm x 40 mm

55 mm x 40 mm  x 16 mm

TIR179 Tiger Iron rough rock

140 mm x 110 mm  x 7 mm

It comes from near Newman in the Pilbara region of Western Australia

Weighs 612 grams

Polished fossil Oncolite slab. ONC112 microbialite 55 mm x 40 mmONC112. 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. 145 mm x 105 mm x 8 mm thick. Weighs 285 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