Polished fossil Oncolite slab. ONC116 Nickeloan magnesite OJ168 A slab

OJ168  A slab

MK501   Mookaite cut and polished on one side with a rough natural back

EU122  Eucryptite rough rock

Dimensions at widest points approximately 140 mm x 120 mm x 50 mm thick

OG209   A matching pair of polished Orbicular Granite halves with natural rough backs

Polished fossil Oncolite slab. ONC116 Nickeloan magnesite OJ168 A slabONC116. 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. 105 mm x 85 mm x 7 mm thick. Weighs 134 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 in