Lightning flashes—while terrifying—appear and vanish in less than a second. Yet, occasionally, passing strikes memorialize themselves with a rocky calling card buried in the earth. Such structures are called fulgurites, also known as “petrified lightning.”

During thunderstorms, the air surrounding a given lightning bolt can get incredibly hot—temperatures exceeding 50,000⁰ Fahrenheit (27760⁰ Celsius) have been recorded. To understand just how scalding that is, note that the surface of our sun only reaches about 10,000⁰ F (5500⁰ C). Naturally, this doesn’t bode well for lightning-strike victims, who often receive severe third-degree burns.

If, instead of a person, lightning hits a sandy beach, an amazing geological phenomenon can take place. Jolted by the sudden, intense heat, unsuspecting sand or rock particles may melt down and re-fuse almost instantly. Thus, a baby fulgurite is born.

These elongated tubes have been found all over the world, from the Sahara desert to the California coastline. Hollow and made of natural glass, fulgurites can reach over 13 feet in length, though a young Charles Darwin once wrote that 30-foot specimens had been reported in England during the 19th century. 

Unfortunately, these glassy objects aren’t noted for their resiliency. Petrified lightning samples tend to get shattered by the elements in short order, making quality samples scarce. However, some passionate tinkerers have created their very own artificial fulgurites with some electrical gear and a few buckets of sand. Check out this awesome video to see how it’s done: