An arched roof supported on its edges and reinforced, when necessary, by ribs.
Any stone used as a decorative facing material which is not meant to be load bearing.
A marble composed chiefly of massive serpentine and capable of being polished. It is commonly crossed by veinlets of other minerals, chiefly carbonates of calcium and magnesium.
Wedge-shaped stone components of a masonry arch, carefully formed to support each other when in position.
A cavity in rock; sometimes lined or filled with either amorphous or crystalline material; common in calcereous rocks such as marble or limestone.