Roman Travertine most represents Roman culture

Roman Travertine is famous for abound of cavern on the surface.In bussiness,researchers usually classify it as the marble kinds.Human has a long history to use this stone.The most reputated building--wrestling ring is primary masterwork of Roman Travertine.Roman Travertine has biege in majority,which let people feel warm and comfortable.Roman Travertine made buildings frequently has a strong historical tastes.Gradually,this kind of stone is applied in many buildings around the world.But why not call marble?Essentially,the travertine is quitely different from the marble from texture and appearance.