Why is this considered Black Metal?

Galvanized Steel Panels Geomembrana Mexico Etching On Aluminum Plate Geomembrana Precio Mexico Aluminum Foil Sticks Exterior Driveway Lights Driveway Reflector Lights Driveway Gate Post Lights Wire And Wood Fence Panels Rough Formwork Tumbled Stones Fine Mesh Wire Fine Mesh Concrete Driveway Sealer Concrete Driveway Resurfacing Concrete Driveway Coatings Concrete Driveway Decorative Concrete Driveway Rough Stone Tiles Rough Stone Flooring