
The Stone Spheres of Costa Rica
26/03/2011 · Hundreds of stone balls have been documented in Costa Rica, ranging in size from a few centimeters to over two meters in diameter. Almost all of them are made of granodiorite, a hard, igneous stone. These objects are not natural in origin, unlike the stone balls in Jalisco, Mexico that were described in a 1965 National Geographic article. Rather, they are monolithic .