Slate is 100 percent natural. it is rougher and uneven, it has good traction for the Beardies and helps keep the nails down. I spot treat the tiles which is easy with a tiny bit of vinger and scrub over the spot with water until it doesn't sound like vinegar. I didn't end up getting tile with the same feel as granite because my Beardies slide around on my kitchen floor and counters. If they dont have good traction, then you can assume that their nails aren't getting filed well (if at all) . And slate looks very natural and feels natural. I think a Beardie would appreciate some traction but that's just my opinion.
Slate is messy when they cut it because it does come right out of the Earth, so if thats the route you go be sure to grab some plastic before running out the door to set it in your car
be sure to measure well. I got 6 pieces cut to size but had to go back and have it re-cut because my measurements were off. (them re-cutting wasnt a problem btw)
I can post a picture our tile later today if you would like?