Summary
Recent archaeological excavations in Southwestern Spain have turned up a remarkable haul of weapons cut from rock crystal buried as grave goods in a series of stone-age1 barrows. The majority of the pieces are arrowheads and microliths of the sort used for constructing a more complex edge2 but the dig also turned up a fairly impressive looking dagger blade.
Apparently creating these blades from rock crystal rather than more traditional flint or chert (or even, given the chalcolithic dating, the up and coming technology of copper) would have taken a significantly greater investment of time and effort. It's not clear if they were practical weapons, or ceremonial ones, deliberately selected to display wealth and prestige and buried as grave goods for the same reason.
Source
Game and Story Use
- Great amusement can be had if the "ancient hero's weapon" turns out to be made of crystal.
- Also an interesting shtick for appropriate undead - bearing in mind that, like their owners, most of the organic parts of the weapons are liable to have rotted.
- Maybe crystal weapons are especially fitted to some kind of enchantment - those related to sunlight for example. If so they might be useful for fighting sunlight vulnerable critters…
- For reasons probably best not inquired into, fantasy tends to associate crystals with psychic powers - you too could climb onto that bus and take these weapons with you.