Polished fossil Oncolite slab. ONC112 microbialite 70 mm x 55 mm

70 mm x 55 mm  x 30 mm

Dimensions at widest points approximately 65 mm x 45 mm x 13 mm thick

Weighs 612 grams

TIR179 Tiger Iron rough rock

Dimensions approximately 130 mm x 100 mm x 50 mm thick

Polished fossil Oncolite slab. ONC112 microbialite 70 mm x 55 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