u/Ayoushy

I bought a mystery crystal box from a crystal wholesaler (ZaienCrystal) a little over a year ago and my dad is not convinced that this crystal in the photos is an actual crystal, but instead marble. I don’t know the name of the crystal to prove him wrong (hopefully) and google image search is showing me images of other crystals.
So can anyone look at the images (same crystal, different sides) and identify what this crystal is called? Thank you!