Flagstone is a sedimentary rock which is cut or split in layers for walkways and patios. It contains feldspar which gives it the blue color. Flagstone is a sandstone which makes the rock essentially quartz. The material that binds flagstone is usually composed of silica, calcium, or iron oxide. The color of the rock usually comes from the cementing material. Typical colors of flagstone are red, blue, buff, and there are exotic colors like chocolate.
It is often used for patios, walkways, and steps in both indoor and outdoor applications. It is recommended that flagstone flooring be sealed for maximum stain and water resistance.