Porto Slate Importers (PSI) is a leading Supplier & Importer with exclusive rights to the highest quality Black Slate Slabs available in the world from Valongo, Portugal. For 50 years, black slate from the Valongo region in the district of Porto, Portugal has been best known for its durability, dramatic appearance, and is the premier choice among architects, builders, contractors, and homeowners.

VALONGO BLACK™ slate has added qualities in all applications, because it is, among all natural stones, the one which measures the best flexural strength, making it best suited for counter tops, building stone, roofing, sinks, monuments, pool coping, sills, ornamental stone, interior and exterior walls, floors, pavers, and many other design projects using Black Slate Slabs from Portugal.