slate

A slate floor is made of multiple slabs, tiles, blocks, sheets, or other forms of slate, a gray metamorphic rock which cleaves easily into flat sheets. It is used occasionally as a flooring material, often in lobbies and public spaces, for the decorative effect of its color and texture.

The stone can be laid in different sizes and forms. Thin sheets are possible because slate cleaves readily along flat surfaces.

Its decorative use in lobbies and public spaces is common but is not a location requirement. The designation concerns the floor surface, separately from slate facade cladding.