Marble is a non foliated metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite (a crystalline form of calcium carbonate, CaCO3). It is extensively used forsculpture, as a building material, and in many other applications.
The features are that the variation has veins through it. You have different densities in , but the color variation and veining is probably the most common feature. You get a very wide range of colors with marble.
There are usually the white, the beige, the greens and the blacks which are very traditional colors.