Polished fossil Oncolite slab. ONC117 chrysoprase CC151 Chrome chalcedony rough rock

CC151  Chrome chalcedony rough rock

It weighs 230 grams

Face is approximately 105mm x 50mm and  7mm thick

Dimensions approximately 130 mm x 100 mm x 50 mm thick

Polished fossil Oncolite slab. ONC117 chrysoprase CC151 Chrome chalcedony rough rockONC117. 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. 160 mm x 80 mm x 8. 5 mm thick. Weighs 217 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