Save your money. Whiskey stones are a funky paradoxical gimmick designed to appeal to an extremely niche hobbyist market, particularly people who fancy themselves whiskey connoisseurs but who aren't all that versed in their whiskeys. Realistically, chilling your whiskey in the first place does more damage to the "smokey, savory nuances" than an ice cube's volume of water ever could. That is to say, if you aren't so terribly fussy about all the subtleties in your whiskey that you honestly enjoy it cold, how much are you really gaining by buying and maintaining and looking after some chunks of soapstone to keep 'em that way, when a few ice cubes will do the same with comparatively minimal impact? Even if you want it cold and you don't want to "dilute" it--and some would argue that a splash of room temperature water in a good glass of whiskey only enhances the flavor--then save the money and the fuss, and just keep the glass chilled or the whiskey chilled in the first place.