These arrow heads are natural Obsidian from Jalisco, Mexico. They are carved into the fin/arrow shape and are see through when held up to the light. These are a fun addition for any collector.
Obsidian is a naturally-occurring volcanic glass that can be deep-black to blackish-green in color. In the past, it was used to manufacture cutting and piercing tools, and it was once used experimentally as surgical scalpel blades. Obsidian is thought to aid in balancing energy in the physical body.