Collector Richard Berger with a “Gogotte” sandstone concretion, found at Fontainebleau (formed during the oligocene, ca 30 million years ago). A Gogotte is a 25-30 million years old natural sculpture created from sandstone, refined by water, hardened by ice, etc. They are collected: 3 days ago a “Gogotte” was sold in a London auction on behalf of the Nat. History Museum. Estimated between £3-5,000, it went for £32,500. @Simon Stahli.