Polished fossil Oncolite slab. ONC113 crystoprase Full round attached to host

Full round attached to host rock

DO196  Dendritic Opal

100 mm x 90 mm x 30 mm thick

chalcedony and magnesite in the one piece

Polished fossil Oncolite slab. ONC113 crystoprase Full round attached to hostONC113. 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. 165 mm x 160 mm x 9 mm thick. Weighs 449 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