Andy from How To Make Everything went out in the Utah desert, gathered up volcanic glass, then through trial and error learned how to make an Aztec-style edge weapon.
The episode includes an interesting history lesson from anthropologist Gilbert Tostevin at University of Minnesota, who shows Andy how Aztecs used a haft embedded with smaller obsidian pieces to make formidable weapons.
• Turning Volcanic Rock into a Blade that's Sharper than Steel (YouTube / How To Make Everything)