Polished fossil Oncolite. ONC109 mookatite CH453 Chrysoprase rough rock

CH453  Chrysoprase  rough rock

195 mm x 135 mm x 14 mm

Dimensions at widest points approximately 240 mm x 140 mm x 13

Weighs 154 grams

Weighs 85 grams

Polished fossil Oncolite. ONC109 mookatite CH453 Chrysoprase rough rockONC109. 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 65 mm x 6. 5 mm thick. Weighs 117 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