The name for dark volcanic glass is obsidian. It is formed when molten lava cools quickly with minimal crystal growth. Obsidian is typically black, but can also be brown, green, or other colors depending on impurities.
The name for dark volcanic glass is obsidian. Obsidian is a black, glass-like material that forms when molten lava cools quickly. It is a type of igneous rock, and is often used for making tools, jewelry, and other decorative items.
