Nantucket Pavers Rivenstone patio blocks are manufactured concrete blocks designed as an affordable natural bluestone alternative with stone texture, clean edges, uniform thickness, and through-color blends. The manufacturer lists Rivenstone in sizes from 12 x 12 through 24 x 36 and colors including Blue, Blue Variegated, and Tan Variegated for patios, walkways, steps, caps, and pool surrounds. Confirm exact size, color, and pallet details before quoting. Nantucket Pavers recommends sand-set installation over compacted free-draining base material.