The Penrhyn Heather Blue slate, also known as Bangor Blue, is one of the most widely used slates. The Penrhyn quarry has been producing roofing slate since the 13th century, and is regarded as being the best in the world. Welsh slate is extracted from some of the world’s finest deposits, formed up to 590 million years ago. Of that extracted only less than 10% is used. They are renowned for the consistency of their colour and texture.
