Polished fossil Oncolite slab. ONC114 beryl Dimensions at widest points approximately

Dimensions at widest points approximately 80 mm x 55 mm x 40 mm thick

BJ136 Polished "Black Jade" A trade name for metamorphosed magnesian tholeiite (basalt)

100% natural

Dimensions at widest points approximately 145 mm x 125 mm x 45 mm thick

One edge slightly unpolished

Polished fossil Oncolite slab. ONC114 beryl Dimensions at widest points approximatelyONC114. 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 100 mm x 7. 5 mm thick. Weighs 241 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