Before I get to this suggestion, let me say that National Geographic’s Break Open 10 premium geode set requires some kind of commitment. But for a group of budding geologists (or kids who think it’s cool to see inside rocks), the payoff is well worth it. Safety goggles and a good hammer are required. I used this Estwing Rock pick for a little extra stability and precision, but a heavy duty hammer will do just fine. There are only 10 stones in the Nat Geo set compared to common geode sets like this test which provided 20 stones. The crystals that appeared on the set boasted far more dazzling colors, shapes, and sizes than the snow-white crystals found time and time again on the general set. If so, there’s also the National Geographic Break Open set of 15 geodes, which is featured in our guide to the best gifts for 7-year-olds.) Depends on the age and propensity of your party. Guests may love watching you break rocks, or they may want to try it for themselves. I asked. (Be sure to wear protective goggles.