This comes from the Apennine mountains in northern Italy. Sediment was laid down in a large sea bed in the area and under pressure formed into limestone. Then in the Mesozoic era the African plate hit the European plate pushing up the land and a ridge of mountains. This movement of the earth's crust fractured the layered stone. Percolating water filled in the fractures with iron and manganese hydroxide. The fractures were then sealed by calcite crystals and the stone metamorphosing into marble. That's how the rock achieved it's "ruin" look. The defined layers in this example show a couple of times where they broke and knitted back together. This rock even sports a pretty little dendrite crystal tree. Marble has a hardness of 3 - not good for gemstones but great for carving.