1 stone = 14 lbs...not sure how healthy this really is. In reality the first few pounds you loose is body weight and then possibly fecal matter. Dieting this way sets up your body for the "starvation" mode if you aren't taking in the correct caloric amounts. Eating healthy is a way of life and dieting extremes can disable the natural weighloss that your body should be using.
White painted stones by Natasha Newton - These would make a nifty place card. Just hand your guests a business card with a matching design on it. Then they get to match the card to the rock at their place. They could then take the rock home as a keepsake.