National Geographic Rock Tumbler Kit – Hobby Edition Includes Rough Gemstones, and 4 Polishing Grits, Great STEM Science Kit for Geology Enthusiasts, Rock Polisher for Kids and Adults

Amazing rock tumbler—turned rough stones into gorgeous polished gems! This tumbler is a total winner for beginners and hobbyists alike. It runs super quietly (barely noticeable even in the living room), stays cool during long cycles, and the barrel seals perfectly—no leaks or mess. I followed the standard 4-6 week process with the included grit/polish steps, and the results are stunning: dull, jagged rocks came out mirror-shiny and smooth. Easy to use and clean, the motor is strong and consistent—no stalling with a full load. Great build quality for the price—feels durable and reliable. My family loves checking the progress every week, and now we have a beautiful collection of tumbled stones for jewelry and display. If you’re into rockhounding or just want a fun, satisfying project, this is fantastic. Highly recommend!

I originally purchased this in March 2024. I used it pretty regularly for 9 months and it worked wonderfully and I loved the results I got with my rocks. I paused using it for a few months and when I tried to start tumbling some rocks again, the tumbler would barely start moving and then would stop all together. Opening it up and cleaning it up seemed to help for a few minutes but then it would stop again. I opened it again and the connections all seemed fine but I wondered if the motor was just worn out. I contacted the manufacturer Think Blue Marble and they immediately replied to my email saying that it sounded like it was a weight sensor issue. They offered to send me a one time replacement free of charge! I provided my address and within 72 hours of my initial email I had received a brand new natgeo tubmler set in the mail! 100 stars for amazing customer service and standing behind their product! I'm just about to finish up the first stage in this new tumbler. Thank you Think Blue Marble!!

I haven’t seen a review (yet) that’s mentioned using this rock tumbler to tumble/smooth sea/beach glass.. so here’s mine & I hope this helps someone out there :) If you’re interested.. I’ve collected so much glass over my years of searching on Lake Erie. Majority of my glass is smooth or frosted over (chef’s-kiss kinda pieces), but of course I have not as-smooth pieces too. I know people say “it’s not ready,” but IMO, it’s ready if my bag is open and it’s not a literal shard of glass lol. Anyways. I’ve heard of people DIYing their own “sea” glass. I FINALLY purchased this, after 2 years of just thinking about getting one. Here’s how I feel about it (using beach glass, not rocks): So far, I’ve been using it almost night & day for about 1-2 weeks. 100/10. If you don’t have a basement, garage, or shed with an outlet, just know it’s a loud & noisy thang! It does wonders for my unfinished beach glass! I only left those pieces in the tumbler for 10-12 hrs (I believe), and they’re perfect now!! Lastly, we listen and we don’t judge: I didn’t read too far into the “what’s included” section, so I was honestly just expecting the tumbler 😂. I love that it came with necklace options, the rocks themselves, an extra rubber- chain(?), and the 4 grit packets. You certainly get your money’s worth. If you made to the end, thanks for taking the time to learn more! :)

My first rock tumbler. Haven't seen or used one since I was in grade school - 60+ years ago. So as a retired STEM teacher I decided to look into geology, now that I have the time, which has always inerested me. (Took astronomy in college but never geology.) I ran my first rocks through the tumbler last month. Used the ones that came with it along with some I collected from the back yard and some I bought at the local "mart". Took a month to get the finished product. Came out reasonably well. Not quite as polished as the photos might suggest. (I used a little mineral oil to improve the sheen.) Not really disappointed, more inspired to try again. Tumbler ran well. Does make a little noise, so I ran it in the garage. You need a workbench anyway to clean and rub the tumbled rocks - a little messy. Requires some water, a plastic basin, a plastic squirt bottle and a soft brush to rince/clean the rocks. Follow the directions and don't rush the process. Some small, soft rocks may disappear during tumbling, simply erroded away. Rather than dump the used grit in your yard (certainly not down any drain) I filtered it through a coffee filter, can and screen sieve setup I made. The sediment can then be dried in the sun and discarded with the trash - recycled back to your local land fill. It will look like light grey plaster. The filtered "grey" water can then be used for limited irrigation in your garden around the edges. (I wouldn't put it around any plant roots. Maybe around bricks or tiles or other masonry. Or just pour it into a drying pan and let the water completely evaporate away?) Pour it down ant holes in the cracks of your driveway, possibly to discourage those pests? I had no issues with the tumbler. It worked fine. I'm ready to start my second run. Addendum: Have now made three 1+ lb runs. Rocks don't shine up very well following included instructions, some completely wore away, so I watched some posted videos. You apparently can get high quality results with this little "hobby" tumbler without the use of mineral oil or varnish or wetting the stones. Will try varying method next run. and probably partially rerun some stones I've already done. Watch some videos to get ideas and teach yourself. Lots of fun - try different things and try not to be too disappointed with first results. In retrospect, I should have spent ~50% more and bought a double barreled 3 + 3 lbd'er. (Like two NG "pro" tumblers). Seems to be what a lot of "rock hounds" prefer.

After only 5 months of use the motor quit. I followed all the directions exactly and didn’t overload the barrel. National Geographic’s supplier of this rock tumbler was quick to respond and replaced the unit immediately!

Are you wondering if it works well? It does! Any problems? None! Results? Incredible, I was truly shocked! Pros: Almost no assembly, at all. Extremely easy to understand the directions (Tumbling time will vary depending on the rocks. Don't let it scare you away when it says one phase should tumble for 6-8 days (I haven't had to tumble any that long! The longest has been 3 days). That being said, an extremely hard rock that's very jagged may need more time. Using the rocks they include, or your own collection of crystals/gemstones is a great route. A plain piece of gravel or a rock of that type is very hard and dense and may take more time (who wants polished gravel anyway though?) Extended project to do with children, lots of engagement. Because their are 4 different grit types with different purposes, the children get to return to their project, dump the rocks and check on the progress and start a new phase. It's a great opportunity to teach to teach about erosion, and show / explain what a rock looks like through millions of years of erosion and then further explain how incredible it is that we are doing this project together that mimics what nature does, we are polishing these rocks in a few weeks that takes millions of years to do in nature! It's a wonderful learning opportunity for children, as well as an extremely engaging project that although it may take quite some time for it to finish, the ongoing project itself is what makes it fun. Returning to the rocks and seeing the progress, (we actually started taking pictures each time we open it so then we can look back on the pictures and see how the rocks have changed!). I cannot say enough how great of a project this is for children to get them excited about science! Personally, I find this to be very satisfying regardless of children. This would be an extremely fun hobby for an adult as well, the above is not to say that this is a children only experience. Use or find or buy your own natural gemstones or softer rocks (look in River beds if you can!). Tumble them, polish them, and then make your jewelry or just save them to display. It's quite a satisfying feeling to see the project from beginning to end, and to know that the beautiful smooth shiny rocks were not store-bought, but that you did this with that with this machine! Cons: I've been through the tumbling process in full, twice now. I honestly cannot think of any cons at this point. It's not to say that no one has had issues, but the machine I received functions perfectly and I have had no issues with leaks or ill-fitting pieces, tearing of the belt or anything of this nature. I did take a very small amount of oil on my fingertip and lightly rub it on the belt to keep it lubricated, with the constant friction I could see how the belt can eventually wear down just like any other belt of this nature whether it's in a car or in a fan. So, keeping it very slightly lubricated will help with the health of the band. Should it break, the kid includes an extra belt and it is incredibly easy to repair, the belt is divisible and an outside piece of the equipment you simply take one off and put the other on there is no sophisticated way of connecting the belt, it is truly something my six-year-old could do with almost no instruction, so an adult will have zero issues with that! If you are interested in rock tumbling, or you just want a very fun project for your children to stimulate their interest in science or to just keep them busy using their imaginations (regarding the possibilities of what to do with the rocks, and imagining whether it will look like and the brilliant colors!) - then this is absolutely a perfect kit to start with. DO: Make sure to not put too many rocks. I've never filled mine more than one third of the way, and I wouldn't recommend doing more than that. The amount of rocks you can tumble at a time will vary depending on the size, but I also recommend not doing anything smaller than a dime because during the tumbling process it could crack and chip. I would also recommend not doing anything larger than a half dollar as well (height and width, and that'd be on the largest size). Remember, this is just the hobby edition. I do have to say though, the results are quite sophisticated for just a hobby edition! All in all, it's an excellent piece of equipment to buy if you're interested in rock tumbling but are unsure if you would stick to it or are not ready to spend a few hundred dollars on a professional Tumbler. ** I did read a few comments about the machine leaking, I have not had this problem at any point. Make sure you are putting on the inner lid correctly, as well as the top lid, then turning the black lid securing piece as tightly as possible. If you do end up having problems, I highly recommend exchanging instead of giving up, because I really have seen that it works and I just want everyone who wants to try this to have the experience I've had! It's been great fun. Wonderful purchase, no regrets!

I think this is a great tumbler kit! I'm new at this hobby and this kit has everything including crystals to do 1 batch. 4 stages of grit included. Barrel is kind of smaller but seems to be a standard size from what ive learned. 2.5#s is a good amount of stones anyways. Very Simple- each stage runs for a week, rinse in between cycles and bam crystals! Super fun, low key project.- requires about 15 minutes if that a week to rinse and restart a cycle. I purchased the extra gems also but not necessity. The finished stones in my Pic are about a 1/3 of the 2 pounds i purchased so I've already started a 2nd batch. Tumbler is not too noisy, i keep it in my attached garage and don't hear it in my house- its on a table with a ledge too-recommended so it doesn't rattle off and fall and break. Does not really seem to move around tho anyways. Can't wait to go to lake huron to collect my own stones

I bought this for my son for Christmas. He's really interested in geology, so I thought that this would be a great way to encourage that interest, add some excitement and show him just how beautiful rocks can really be. I'm very glad I chose this rock tumbler. There were others that were cheaper, but after careful consideration of several reviews and ratings, this one stood out. The machine is very easy to use. The instruction book that's included provides simple directions for use and everything seemed to be labeled so that it was all quite easy to put together and use within minutes. The only thing my son couldn't manage himself was getting the lid on and off because it's so tight (which is a good thing if you don't want leaks!). I was a bit skeptic, since it takes nature so many years to accomplish such beauty, but my son and I placed the rocks, grit and water into the container and set it for our first run. Surprisingly, after just using the first grit, the rocks look amazing! We had even added some that he'd found on our evening walks around the neighborhood and we couldn't believe how they turned out! Again, that was after just the one week's worth of time (168 hrs) with the first grit. The only downfall is that the machine really needs to run constantly for each of the polishing periods, which some might consider long. It can be difficult since it's pretty loud. His dad absolutely hates how loud it is and doesn't want it to be running at night, so we had to break up our run time. That resulted in it taking us two weeks to get our "7-day" results. We were satisfied with those results for now, so we haven't yet done the next round of grit and run time. So far, this machine does exactly what I expected of it. Yes, it's loud, but it's not nearly as loud as some of the other machines out there. I imagine that is due to the rubber container. In addition, the included rocks are a great way to get your kids excited about geology! We're now planning a summer rock-hunting adventure so that we can really utilize this rock tumbler and some of the other new tools we have at our disposal. For the record, the one and only reason I would give this rock tumbler less than 5 stars is because it's loud. But you know what? Rocks banging together are not quiet in nature, so I don't expect any different when they're in a man-made machine. You shouldn't either. Oh, and anyone thinking that rock tumblers take too long (or something you might tell your kids when they complain that it's taking too long)...patience is a virtue. Consider how long it took for that rock to form in the first place, and be thankful that you have a machine at your disposal to make your finds look amazing in a minute percentage of the time that it took nature to create them.