There’s a lesson in here somewhere
Looking up something entirely unrelated in Wikipedia, I found a picture of a 15th-century Aztec sword:
They were called Macahuitls, made of obsidian blades set into a wooden core. They were far from a primitive substitute for a steel sword–in fact, they were about five times sharper. (According to the source article, the best modern surgical scalpels have obsidian-edged blades.)
Unfortunately, Macahuitl blades were terribly brittle, which made them shatter uselessly against Spanish metal armor. Aztec armor was made of wood, so the issue had never come up before.