by havires
Over the past few decades, miners near the little town of Ottosdal in Western Transvaal, South Africa, have been digging up hundreds of mysterious metal spheres. These spheres measure between 25 and 100 mm in diameter, and some are etched with three parallel grooves running completely around the equator. Two types of spheres have been found. One is composed of a solid bluish metal with flecks of white, the other is hollowed out and filled with a spongy white substance.
These spheres are reportedly so delicately balanced that even with modern technology, they would need to be made in a zero gravity environment to attain these characteristics. These objects have become known as the Klerksdorp spheres.
Here's related reading to what I quoted