Ardragh Quarry, Maam Cross, County Galway

This example contains both metamorphic and igneous rock-types. The green, banded rock that comprises the majority of this specimen represents a series of metamorphosed lava and ash from volcanic eruptions that took place between 600 and 650 million years ago.

At a later date, possibly during the formation of the Galway Granite, the banded metamorphic rock was intruded by molten material that has crystallised to form a rock-type known as aplite.

The dominant mineral in the metamorphic rock is dark green amphibole, hence the name ‘Banded Amphibolite’.

At Maam Cross Quarries the stone is crushed to form aggregates for the Irish building industry.