That's Gneiss! The Unbridled Enthusiasm Of Geology Professors

Every geology professor experiences that moment of pure joy when a student asks about a rock specimen. That facial expression says it all - a mixture of "I've been waiting my entire career for this question" and "I'm about to launch into a 45-minute explanation about metamorphic banding patterns that will make absolutely no one but me excited." That's gneiss (pronounced "nice") - both the rock in the image and the pun opportunity no geologist can resist. The striped pattern is practically begging for a detailed explanation of mineral segregation under intense heat and pressure. Students, beware: never ask about rocks unless you've cleared your schedule for the day!