Polished Porphyry slab. PO 128

PO128.  Pink porphyry slab, cut and polished  on one side.

From Mindoolah, Western Australia.

Dimensions at widest points approximately 110 mm x 85 mm x 8.4 mm thick.

Weighs 213 grams.

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.

The porphyry pictured here has pinkish coloured clinozoisite crystals set in a ground mass of dolerite.

The clinozoisite has replaced but retained the shape of plagioclase feldspar crystals.