When lightning hits sandy soil with enormous heat—often hotter than the surface of the Sun—it instantly fuses the minerals into long, glassy tubes known as fulgurites. These rare formations are sometimes called “frozen lightning” because they capture the path of an electrical strike in solid form beneath the ground. Important Details: • Fulgurites form when lightning heats sand to over 1,800°C, melting silica into natural glass • Their hollow, branching shapes trace the exact route of the lightn