The immense pressure created by the movement of the earths crust fractured the limestone.
The cracks were later sealed by the deposition of calcite crystals.
This event is thought to have occurred some 50 million years ago.
In Renaissance Europe, they were highly regarded and were in much demand in the Royal courts.
Sometimes the natural landscape in the stones were completed with painted figures, mythical creatures and objects.
Besides, the pattern is hidden inside the rock and cannot be seen until you break it open.
Nevertheless, there seems to be no shortage of ruin marble specimens among collectors and jewelers.
Photo credit:www.christies.com
Sources:Earth Story/parenthetically.blogspot.in/www.spiritrockshop.com/Wikipedia/www.pietrapaesina.com
