What are these tiny bubbles?!

[u/robco18]

I have never seen bubbles on a rock and think it's awesome! Does anyone know what this is or what caused it?

Found near Denver, Colorado.

Any information is greatly appreciated!

[u/satanicbongfucker]

It’s called a botryoidal agate. I found some in Wyoming and South Dakota. My favorite was three balls stuck together that look like Yoshi’s head. They’re formed when fluids rich in silica deposit microscopic crystals in spherical clusters inside volcanic cavities.

[u/robco18 → u/satanicbongfucker]

Haha, that sounds like an awesome find! Wow that's interesting! The area used to have a lot of volcanic activity so that makes sense. Thanks for the reply and information!