This is an old pic from the Smithsonian Natural History museum. The geology wing, I think. It was supposed to be an example of gems refracting light or something.

On a side note, if you ever get the opportunity to go to a Smithsonian, fuckin do it. People, they had literal meteorites the size of sedans just sitting there with a sign on it encouraging you to touch it. I touched a fucking hunk of metal that had been careening through the void for a number of years my little monkey brain has trouble grappling with. Sorry. It left an impression. Go if you get the chance