Marble/Granite Tiles

Its almost summer and I've been wanting to get some tiles for my chinchilla. I live in Vancouver so summer doesn't get too hot and the chinchilla cage is where the temperature is pretty much 3-4 degrees lower than the temperature outside



I was looking into buying marble and/or granite tiles from home depot to put in her cage so she has a place to lay down on when it does get a bit warmer or when she wants to cool down.



Is there anything I have to do to the tiles to ensure their chin proof? Like look for any coatings I can't have on it or such?



Thanks! =)