I just had an idea to give my dragon culture stone currency instead of metal coins. I don't mean precious stones, or at least not just precious stones. I mean semiprecious stones that can be cut into three-dimensional shapes that can be used for currency. I have a few questions: Are stones heavier than coins in general or are they actually lighter? I suppose it depends on the metal and the stone... If you made a mistake when cutting the stone, wouldn't you have to scrap it? What would they do in that case? Aren't stones easier to damage than metal? Maybe this isn't a good idea. Is there some kind of treatment one could use to harden the stones so they wouldn't crack, negating the issue in the previous question? Could a dragon use its fire to melt the stones so they could be forged in a mold similar to metal? Or would a) the fire not be hot enough or b) the mold be impossible to make from anything that didn't melt before the rock did? How much weight in pebbles would be manageable to fly with?