Best heat absorbing Stone for Basking Area?

Hi,
I am looking for the best kind of stone to put on my basking area which can absorb heat
very well and can release it slowly so that my snake is kept warm.
What kind of stone material would you suggest?

BP's don't really "bask". They aren't fond of bright light or just hanging out in the open.

If you want to try it and see how it goes anyway, having your heat source on a reliable thermostat is even more important than usual because it can burn them a lot faster than ambient temperature or substrate temperature. Pretty much any mostly smooth stone that isn't really brittle and porous should work. You will want to clean it really well to make sure it doesn't have any chemicals or bacteria on it. If you don't care about natural aesthetics, a piece of tile would work great after sealing the bottom with a thin layer of 100% silicone caulk and letting it cure away from the snake for at least 48 hrs.