Limestone and slate are sedimentary rocks formed over millions of years by particles of sand, stone and shell compressed in layers at the bottom of our seas and waterways, producing a hard stone. Limestone is often known for its high fossil content and is generally cream or white in colour, while slate has a more uniform patina, darker than limestone, slate is available in greens, greys and blacks. Both have a honed appearance; they are softer and cannot be highly polished. Limestone is a very popular choice in bathrooms while slate is often used for bathrooms and hearths.