Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of the Earth. Basalt is used in construction as building blocks and cobblestones and is also commonly used used for flooring, statues, monuments, worktops, window sills and wall cladding. Heating and extruding Basalt yields stone wool, an excellent thermal insulator.
Take a look through some of the colour variations available.