Calistoga is a colorful castle rock style natural stone veneer with a tumbled finish.  The stone is cut from sheets of natural quarried stone and showcases only the bedfaces.  The bedfaces are the tops and bottoms of the natural stone slabs.  For reference, the flat surface of an active quarry that you walk on and drive across is referred to as the bed.  Calistoga has some eye-catching color variation from the changes in mineral composition between the layers of the stone.  Each piece of Calistoga has been machine split on all four sides to create the rectangles.  The resulting sharp edges get rounded off in the tumbling process.