Polished fossil Oncolite slab. ONC114 dendrites NJ433 A rough rock

NJ433  A rough rock

From the Greenbushes mine in southern Western Australia which is the largest operating lithium mine in the world

80 mm x 65 mm x 45 mm

It weighs 476 grams

Dimensions at widest points approximately 165 mm x 105 mm x 9 mm thick

Polished fossil Oncolite slab. ONC114 dendrites NJ433 A rough rockONC114. 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 100 mm x 7. 5 mm thick. Weighs 241 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