Something like this came up in Robert R. McCammon's 1987 book Swan Song[1], one of the first novels to win the Bram Stoker award[2] for Best Novel (alongside Stephen King's Misery that year).

One of the survivors finds a glass ring (something like trinitite) among the post-nuclear-blast rubble of Saks Fifth Avenue[3] in New York and sees visions of the future (or something) through it.

[1] https://en.wikipedia.org/wiki/Swan_Song_(McCammon_novel) [2] https://en.wikipedia.org/wiki/Bram_Stoker_Award#External_lin... [3] my memories of this book may be embellishing this a bit....

For God's sake man! You must learn to shield your thoughts from the crystals!

Found footage movie, combining Trinity Test and Philadelphia Experiment maybe? I think it has legs

Or the start of a new cult?

Which could also result in a B movie, I guess.