Portland Stone

Notes:

An extremely pure limestone, pale greyish-white to cream in colour. It is fine-grained, oolitic (being largely composed of tiny calcite spheres called oolids), and fossil rich in certain beds with oysters, bivalves and gastropods dominating and some algae which indicates deposition in shallow water. Portland Stone which is a grainstone, formed in marine, sub-tropical environment where it formed a number of distinctive horizons or beds. The fossil-poor Whit Bed provided the premier freestone from Portland. It is capable of being worked and carved in any direction. Highly regarded as a building stone and worked for at least a millennium, it was widely used from the early 1600s in England and was favoured for many 19th century buildings in Dublin, and is still quarried today.