Pennsylvania Bluestone is a layered sandstone found only in the northeastern tier of Pennsylvania, parts of northern New Jersey and the southern tier of New York. The quarried product has many uses, from cut dimensional stone used in patios, walkways and stair treads to architectural stone used in buildings. It is also used for wallstone, decorative boulders, natural steps and other landscape features. The name Pennsylvania Bluestone is due to its predominantly blue color and because the majority of stone is quarried in Pennsylvania; it can, however, appear in many other hues besides blue. It was formed over 360,000,000 years ago during the Devonian Period as large inland seas deposited sand in the Catskill delta region. It is composed of feldspar, sand, and mica (among other minerals) and is clear of most organic residues. Pennsylvania Bluestone is a layered sandstone found only in the northeastern tier of Pennsylvania, parts of northern New Jersey and the southern tier of New York. The quarried product has many uses, from cut dimensional stone used in patios, walkways and stair treads to architectural stone used in buildings. It is also used for wallstone, decorative boulders, natural steps and other landscape features. The name Pennsylvania Bluestone is due to its predominantly blue color and because the majority of stone is quarried in Pennsylvania; it can, however, appear in many other hues besides blue. It was formed over 360,000,000 years ago during the Devonian Period as large inland seas deposited sand in the Catskill delta region. It is composed of feldspar, sand, and mica (among other minerals) and is clear of most organic residues.