Polished fossil stromatolite from Bolivia. BST105 striped Porphyry is a general term

Porphyry is a general term that is used rather loosely for  igneous rocks which contain relatively large isolated crystals set in a fine-grained groundmass

Weight is 757 grams

From near Newman in the Pilbara region

5 mm thick at widest points

170 mm x 70 mm x 60 mm thick & weighs 763 grams

Polished fossil stromatolite from Bolivia. BST105 striped Porphyry is a general termBST105 Fossil stromatolite slab, polished on one side. This museum quality specimen has been cut at right angles to the bedding and displays the columnar structure beautifully ! From the Miraflores Formation, El Molino, Potos, Bolivia, South America. Age approx. 70 million years (Cretaceous) Dimensions at widest points approximately 345 mm x 180 mm x 8 mm Weighs 1,065 grams