Obsidian and basalt are both igneous rocks, meaning they are formed from the cooling and solidification of molten rock. However, they are distinct rock types with different properties:

* Obsidian is an extrusive igneous rock, meaning it forms when lava cools quickly on the Earth's surface. It is known for its glassy texture and dark color.

* Basalt is also an extrusive igneous rock, but it has a more crystalline texture than obsidian. It is often found in volcanic flows and is typically dark gray to black in color.

While both are igneous rocks, they differ in their cooling rate, texture, and mineral composition.