SPF131 Fossil stromatolite .
Rough rock with natural back, cut and polished on one side.
These are the oldest known fossils on Earth.
From the Strelley Pool Formation in the Pilbara region of Western Australia.
Age is approx. 3.4 billion years.
Dimensions at widest points approx. 155 mm x 70 mm x 30 mm thick.
Weighs 648 grams.
