Lithophysa

Lithophysa, also known as lithophysae, are little pockets or bubbles that form in volcanic rock like obsidian. Imagine playing with Play-Doh and squishing it really flat to make a pancake. Now imagine poking little holes into that pancake with your finger. That's kind of like what happens when hot lava cools really quickly to form obsidian, but instead of using your finger, the rock forms little gas bubbles or pockets. These pockets can be big or small and they can be round or weirdly shaped, like a star or a flower.

Scientists study these lithophysae because they can tell us a lot about how the volcano erupted and how the lava cooled. They can also be really pretty to look at, with different colors and textures inside the bubbles.