A brittle rock made of glitter. It breaks in this linear fashion and can be pound into sand by a mortar and pestle.

Anyone got any clues?

Edit: Thanks for all the answers. I found it in Romania and after searching for forums of minerals from Romania, I got a few other clues.

It isn’t conclusive to me yet, but the possibilities are:

  • Pyrit
  • Mica
  • Schist
  • Nagyágit
  • Calaverit
  • Sylvanit

Of these, Mica and Sylvanit fit the best (imo).