Kirkby slate is a sedimentary metamorphic stone formed in the Silurian period, some 300-350 million years ago. In its natural state it is an even blue grey colour throughout, and it hones to a matt black colour, producing a homogenous, dramatic, impactful stone. Architects and designers around the world have long taken advantage of its uncomplicated and striking natural beauty, durability and adaptability to create classic weather resistant details and surface finishes.