Moruya Tonalite

This is a coarse-grained specimen of the Moruya Tonalite from the south coast of New South Wales. The rock is part of the Moruya Plutonice Suite and is mostly comprised of plagioclase (white), quartz (light grey), biotite (black) and large prisms of hornblende (also black). Accessory phases include sphene (visible as small reddish crystals in hand specimen), apatite and zircon. The rock was quarried from a quarry on the Moruya River and was used for several projects including the breakwall at Moruya Heads. More famously, it also forms the outer casing to the pylons of the Sydney Harbour Bridge.