Construction marble is a stone which is composed of calcite, dolomite or serpentine which is capable of taking a polish.  More generally in construction, specifically the dimension stone trade, the term "marble" is used for any crystalline calcitic rock (and some non-calcitic rocks) useful as building stone. For example, Tennessee marble is really a dense granular fossiliferous gray to pink to maroon Ordovician limestone that geologists call the Holston Formation.