Green in colour and often highlighted by contrasting veins which emphasise its natural origins, Brossen Stone slate is a metamorphic volcanic ash from the Borrowdale Volcanic Group laid down 450-500 million years ago during the Ordovician period and is prized by architects for use as an exterior and interior architectural stone. Brossen Stone has long been used to provide cladding, flooring, paving, cills, and copings, with its rich, dark, contrasting green tones creating subtle colour changes to add life and character to any domestic or commercial project.