Several years ago, a team of archaeologists excavating the megalithic tomb of Montelirio tholos in Spain uncovered a remarkable 5,000-year-old dagger, measuring 8.5 inches (about 22 cm) in length, crafted entirely from rock crystal.

Alongside the dagger, the team discovered ten arrowheads, four blades, and a crystal core used for tool production—all made from the same rare and visually striking material.

These artifacts reflect a high level of craftsmanship and are believed to have held significant ritual or symbolic importance in prehistoric society.