https://en.wikipedia.org/wiki/Trinitite
A material similar to trinitite can be formed by meteor impacts, these are impact glasses.
Impactite
https://en.wikipedia.org/wiki/Impactite
Impactite is an informal term describing a rock created or modified by the impact of a meteorite. The term encompasses shock-metamorphosed target rocks, melts (suevites) and mixtures of the two, as well as sedimentary rocks with significant impact-derived components (shocked mineral grains, tektites, anomalous geochemical signatures, etc.). In June 2015, NASA reported that impact glass has been detected on the planet Mars... When a meteor strikes a planet’s surface, the energy release from the impact can melt rock and soil into a liquid. If the liquid cools and hardens quickly into a solid, impact glass forms before the atoms have time to arrange into a crystal lattice. Impact glass is dark brown, almost black, and partly transparent.
and from the FRchives, a King Tut angle:
http://www.freerepublic.com/tag/impactite/index
Or Alamagordo glass or atomsite. Illegal to find some and stick it in your pocket now, believe it or not.
My grandmother, long gone, was a rock hound. She visited the Petrified forest before it was a park and picked up some petrified wood for her rock garden. Sure that’s illegal now too.
I have a piece of Libyan desert glass
Interesting stuff
"Glass is a supercooled liquid whose viscosity has become so high that for all practical purposes, it is a solid."
Glass experts know that a glass beam supported at the ends, with a weight hanging from the middle, will become measurably bent after many years due to slow viscous flow due to rearrangement of internal bonds.
Glass formation from thermonuclear melting of silicates is not at all an unexpected result. Compared to metals, molten silicates are very viscous and do not recrystallize very quickly.
Melting of high-purity (quartz) sand is an industry for making glass articles for high-temperature service. The names for this glass are "fused quartz" or "vitreous silica." Its desirability in manufactured articles is that it shows very high resistance to thermal shock breakage because of its very low thermal expansion coefficient.
A sister laboratory and kitchenware product is Corningware's Pyrex (TM) glassware featuring very high silica content, made workable by its boron content.
One of the methods of "disposing" of nuclear waste is by melting the radioactive products with suitable glass-maker compounds to tie up the fissile atoms, then pouring the resultant glass into corrosion-resistant, mechanically strong stainless steel tubes, capping them, and storing these "logs" underground in dry caverns; which can then be protected from access.