CompuServe Thread

Hi Kim… One way is to use a lapidary saw…I've also seen them cracked open by tapping around a circumference with a hammer much like opening a coconut. One guy had a special large settup somewhat like a pair of bolt cutters to clip them in half. Note that of the above methods, only the use of a lapidary saw will produce a smooth cut surface which can be polished so if your student saw a polished geode it was most likely sawn through first. -Russ

Hi, Kim The best way to cut a geode is to use a lapidary saw with a diamond blade. (That is, a steel blade impregnated with diamond dust around the rim.) The blade runs partially submerged in some sort of coolant (oil, or water with chemicals to reduce rusting of the saw) and the stone is mounted in a vice hooked to a screw or hydraulic cylinder that advances the stone into the blade. the whole thing is mounted in an enclosure to keep the coolant from spraying all over. These saws aren't cheap, but you might find a local 'rock shop' with one that would cut the stone for you for a nominal fee. (They usually charge by the square inch.) Check the yellow pages under lapidary. If you can find a local mineral club, one of the members is sure to have the equipment and might be talked into cutting the rock for free. One of my friends once took his saw to his son's grade school and spent a day cutting whatever stones the students volunteered. However you arrange to get the geode cut, it would be best if your student was there to see the process. That way he or she would get the chance to be the first person in the universe to see the inside of that particular geode. Depending on the geode, that could be most exciting, or incredibly boring. <g> Have a Very Merry Christmas! Guy

Hi, Kim At a Tucson show I saw a relatively simple system in operation as part of a "pick your geode and have it opened" for $5.00. The nut-cracker was one of those hydraulic rams that body-shops (repair your smashed auto) use. The ram was bolted to a length of steel joist. The piston head had a guillotine blade bolted to it while the end of the joist nearest the blade had a vee shaped piece to hold the geode (a jaw from a pipe vice, think). There was a piece of chain that wrapped over the geode and was held in place by a bolt that slid into a hole in the joist just in front of the vee shaped jaw. The geode was "chained" against the jaw, the ram was pumped until the blade broke thru the geode. The bang was worth at least $4.50. I think the ram was fixed to the joist in a way that the distance between the blade and the jaw could be varied to accomodate wallnuts to coconuts – a series of bolt-holes in the joist. It all worked very well. This sounds like a good end of school year project. Usual disclaimers for injuries caused by flying nut fragments. Chris