Pennsylvania Bluestone Thin Natural Stone comes from a quarry in Pennsylvania, near the New York-Pennsylvania border. It's known for its variations in colors and aged, mossy look. It ranges in color from blue, purple, green, and grays with hints of rust colors and moss. This particular version of Pennsylvania Bluestone Medium is approximately 3" to 4" thick and as an irregular stone, it comes in many different sizes. Only need a few specific pieces? Visit our store and get what you need from our easily accessible pick bins! Coverage: *One ton covers approximately 70-80 square feet. Larger gaps increases coverage and large pieces decreases coverage be reducing the number of gaps.