I bought two of these, one for my daughter and one for my niece. My daughter (aged 5 at the time) had a great time chipping away at the rock to get all of the gems out. True, it did take her quite a while (and she switched off for a bit with her 7-year-old sister), but the only time I had to intervene was to suggest she wet the rock to make chiseling a bit easier. All told, it took a few hours (which, as a parent of four, was *brilliant*!) and resulted in quite a few nice polished stones. She keeps them in the included leather pouch and considers them one of her valued "treasures."