Slate industry in Spain

90% of Europes's natural slate used for roofing originates from the slate industry in Spain, with the region of Galicia being the primary source of production.

Slate is a fine-grained metamorphic rock that splits into thin, smooth-surfaced layers. Metamorphic rock is rock which was once igneous or sedimentary and has been subsequently subjected to heat and pressure in varying degrees thereby altering its composition, structure and appearance. It is used extensively in the building industry, particularly for roofing tiles. The production of slate is estimated at 4 million tons per year.