Obsidian

Obsidian is a natural volcanic glass that forms when lava cools quickly. This rapid cooling process prevents crystals from forming, resulting in a smooth, shiny, and often black surface. Obsidian is found in areas with high volcanic activity, such as the western United States, Mexico, and parts of South America. It has been used for thousands of years by indigenous peoples for weapons, tools, and even jewelry due to its sharp edges and striking appearance.