Polished fossil Oncolite slab. ONC117 chrysoprase TI284 Tiger Iron slab

TI284   Tiger Iron slab

Dimensions at widest points approximately 105 mm x 70 mm x 9

CC151  Chrome chalcedony rough rock

Polished petrified wood slab

Polished fossil Oncolite slab. ONC117 chrysoprase TI284 Tiger Iron slabONC117. 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. 160 mm x 80 mm x 8. 5 mm thick. Weighs 217 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