Also mistaken for fulgurite by the more naturalistically minded, apparently. Maybe most common in the Nordics, based on viking references?
Additional links:
https://www.nationalgeographic.com/science/article/100810-thor-thors-hammer-viking-graves-thunderstones-science
https://fi.wikipedia.org/wiki/Ukonvaaja [Finnish]
It’s gotten so fast that we now see significant changes in our lifetimes - cultural, technology, climate. For most of human history, it took many generations for any real change to occur.
Japan might be the record holder for fastest significant change, though. Feudalism to a modern industrial economy in a few decades.