First of all, these whiskey stones are ultra cool. Having received them as a thoughtful birthday gift, it would be wrong of me to disparage them. They work exactly as advertised: throw one in your rocks glass (OK, don't "throw" it or you'll end up with broken glass), pour in some straight whiskey or bourbon, and enjoy your drink dilution free. Leave it to my friends to try and use them in a rum and Coke (diet and warm, no less), and they do not cool down your drink. I decided to see what the temperature of the stones were straight out of a house hold freezer using my infrared thermometer. As you can see, the temperature is around 8 to 9ºF and was consistent across the stones. Surprising?