Sedimentary stones that have high contents of quartz and silica are included in the commercial definition of "quartz-based" stones. Stone types such as sandstone, bluestone, and brownstone are included in this group. The quartz grains in such stones are cemented together by another material, commonly silica, iron oxide, or calcium carbonate. A wide variety of oxidized trace minerals will account for varying colors from light buff, to dark blue-gray, to reddish brown.
Being sedimentary in origin, all quartz-based stones have specific bedding planes and a pronounced anisotropic behavior. (stonebuy)
Quartz based stones have been used for centuries as flagging materials, ashlar, copings, sills, hearths, and mantles. Modern fabrication capabilities allow its use in cladding applications, although it will generally be of 3" or greater thickness
