I absolutely love these dice, but do be careful with them. I keep them in the included bag and make sure that they are packed in such a way that theres little to no wiggle room, and always make sure to carefully remove them and put them back, but at one point the d8 came out with one of the corners sheared right off. It was able to be fixed with just a dab of superglue, but I haven't used them since it happened because I don't know how well it is going to hold up, and they are now just for display.
LaserEmuFYI, when I spoke to the MDG folks at GenCon, they told me that if a stone die breaks under reasonably gentle use and storage, they'd replace the die. That's the only reason I took the plunge and got these and the Opalite set.