Polished fossil Oncolite slab. ONC115 asperia ashburtonia Dimensions at widest points approximately

Dimensions at widest points approximately 80 mm x 40 mm x 16 mm thick

BJ114 Polished "Black Jade" A trade name for metamorphosed magnesian tholeiite (basalt)

From near Norseman in the Eastern Goldfields region of Western Australia

most commonly the green chromiferous muscovite mica

Approximate dimensions at widest points 130 mm  x 115 mm  x 12

Polished fossil Oncolite slab. ONC115 asperia ashburtonia Dimensions at widest points approximatelyONC115. 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