GEOLOGY HUB on Instagram: "GeoCat here, ready to dig into the rocks with you! Let’s talk about… OBSIDIAN! 🪨 What is Obsidian? Obsidian is a type of volcanic glass. It forms when lava cools down super fast — so fast, in fact, that crystals don’t have time to grow. That’s why it looks smooth and shiny, like black glass! #geologypage #geology_hub #geologyfieldwork #geologist #geology #geocat #geologyrocks⚒ #geologytrip"