5,000 year old quartz crystal dagger with ivory hilt.
The dagger is 8.4 inches (214 mm) in length, 2.3 inches (59 mm) in maximum width, and half an inch (13 mm) in thickness.
It was discovered in a megalithic tomb in Valencina de la Concepción, Spain. The bodies of 25 individuals were also recovered. An analysis of the remains revealed just one male with the rest being female; all of them had drunk some sort of poisonous substance.
One thing to note is that there were no crystal mines in the region, so the artisans had to have travelled long distances to find the crystals. The rarity of the crystal materials suggests that these weapons were reserved for a select group in the community.