Polished fossil Oncolite. ONC111 #brecciated CH453 Chrysoprase rough rock

CH453  Chrysoprase  rough rock

120 mm x 90 mm x 45 mm

CH437  Chrysoprase  slab polished  on one side

170 mm x 125 mm  x 9 mm

Rough Gaspeite

Polished fossil Oncolite. ONC111 #brecciated CH453 Chrysoprase rough rockONC111. 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