Traditionally the term Marble was used by stone masons to describe any stone that would take a polished finish.

From a geological point of view however, Marble is defined as Limestone which has been subjected to thermal metamorphism.  This process of metamorphism leads to a dense, closed surface although some material may have slight open veining or surface pitting.  

Marble has been used in ancient buildings for millennia due to the vast spectrum of beautiful shades and mineral veining.  Some Marble tiles or slabs with particularly prominent veining may have a mesh backing applied, predominantly to reinforce the material during transport and cutting.  Marble is a very dense stone that readily lends itself to a polish but is also available in Honed and Tumbled finishes.