Polished fossil Oncolite. ONC111 #brecciated Dimensions at widest points approximately

Dimensions at widest points approximately 250 mm x 145 mm x 10 mm thick

The quartz epidote axinite mineralisation was evidently caused by hydrothermal activity related to the doleritic sills which are in close proximity to the occurrence

From near Yalgoo

CH453  Chrysoprase  rough rock

CH437  Chrysoprase  slab polished  on one side

Polished fossil Oncolite. ONC111 #brecciated Dimensions at widest points approximatelyONC111. 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