Pennsylvania Bluestone is one of the most widely distributed domestic flagstones in the U.S. It is a very durable and predictable stone with a pleasing earthy color palette. The name "bluestone" can be somewhat misleading as this material is really a "full-color" stone in hues from blue/gray/green/brown and lilac. It is available in all blue - referred to as BlueBlue, Lilac or Lavendar and Full-Color which includes a range of everything and is the most commonly specified and widely available.