From my collection.Its not militaria,but it is connected to WW2 history.At 05:30 July 16,1945 these rocks were formed.The most common name is Trinitite.But AKA Alamogordo glass and atomsite.These I traded for when I was a mere kid in the mid 1960's.We lived in New Mexico and like most young lads I liked to drag home all kinds of what my mother referred to as "crap".Our neighbor had a bucket of the stuff he collected before it was shut off.I showed such interest in the stuff he gave me a handful of it.I still have 3 pieces of it traded the rest off over the years.Link provided for more info on it. the photo shows a top and base of 2 specimens.
https://www.lanl.gov/museum/news/newsletter/2018/04/trinitite.php