I am planning an RPG adventure where the characters might end up getting a large cubic lump of "gold", which in reality, as you might have guessed, is in fact pyrite.
I also wanted to plan for the contingency that the group wouldn't notice that it's not the real deal, so I thought I could maybe let one of the characters cut himself on the crystal. A quick google search yields images such as this: (Source)
This looks pretty sharp and possibly blood-drawing, but is there a way to know for sure? Any recommendations as to how to handle sharp minerals? Any first-hand experiences?