The Lanzhou screw is a mysterious object discovered in recent years that seems to challenge mainstream archaeology and history. It was discovered in 2002, and has since then, generated great amount of attention among researchers. The most mysterious part of this object is that, within a piece of rock, a metal screw was discovered. The mysterious pear-shaped stone is about 6×8 cm and weighs around 466 grams. But it is not a common rock and the metal shaped screw inside just adds to the mystery of a rock, that according to researchers is around 300 million years old.
The mysterious black rock has geologists scratching their head. Tests have failed to show the exact composition of the mysterious rock, researchers that include geologists and physicists from the National Land Resources Bureau of Gansu Province, Colored Metal Survey Bureau of Gansu Province, the Institute of Geology and Minerals Research of China Academy, Lanzhou Branch, and the School of Resources and Environment of Lanzhou College, are unsure of the origin of the artifact and point out that at this time, all theories are possible.