Polished fossil Oncolite slab. ONC115 oldest agate in the world The amphibolite

The amphibolite

OJ192  A rough rock

20 pieces  of rough green Beryl

PA277  Pilbara Agate

Weighs 654 grams

Polished fossil Oncolite slab. ONC115 oldest agate in the world The amphiboliteONC115. 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. 170 mm x 70 mm x 7. 5 mm thick. Weighs 211 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