Sardinia broke apart from Spain and France more than a 100 million years ago, during the opening of the Mediterranean sea as a consequence of mid atlantic ridge spreading. Since, Paleozoic granite has been uplifted, eroded and exposed during the Tertiary. Blocks tumbled downhill and are found amidst forrests.
Sardinia is the second-largest island in the Mediterranean Sea (after Sicily). The area of Sardinia is 24,090 square kilometres (9,301 sq mi). The island is surrounded (clockwise from north) by the French island of Corsica, the Italian Peninsula, Tunisia and the Balearic Islands. Sardinia is a constitutional part of Italy, with a special statute of regional autonomy under the Italian Constitution. http://en.wikipedia.org/wiki/Sardinia