Marble is a metamorphic rock. Formed by compression of millions of tiny fossilized shells into calcium carbonate, in its purest form it is a white like the Italian Carrara marble. In other areas the water percolating down through the rock introduces different minerals whose reaction causes the spectacular colouring and veining so prized for centuries. It is still possible to find small fossils within the stone. Marble is spectacularly beautiful but because of its porosity of it is prone to staining by such things as red wine and oil. This is why granite is the preferred type of stone for kitchen worktops, while marble is generally used for bathrooms. If you really have to have marble in the kitchen (and these remarks would also apply to limestone, slate and honed granite) then great care must be taken to keep it well sealed.
Due to the fact that marble is natural, marbles vary dramatically in colour and slab size. This is merely a representation of material available. Please enquire for more details.