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💎 Turn ordinary rocks into extraordinary gems—because your hobby deserves to shine!
The National Geographic Hobby Rock Tumbler Kit is a durable, quiet, and easy-to-use STEM activity designed for ages 8 and up. Featuring a powerful motor, leakproof barrel, and a complete set of polishing grits plus nine real rough gemstones, it transforms rough stones into polished gems. Perfect for educational family projects or personal hobbies, this award-winning kit offers a hands-on geology experience that mimics natural erosion in just weeks.





| ASIN | B01LQCIL88 |
| Age Range Description | 8 years and up |
| Best Sellers Rank | #1,808 in Toys & Games ( See Top 100 in Toys & Games ) #1 in Kids' Rock Tumblers |
| Brand Name | Blue Marble |
| Customer Reviews | 4.5 out of 5 stars 25,919 Reviews |
| Educational Objective | STEM |
| Global Trade Identification Number | 00816448020421 |
| Included Components | Complete Rock Tumbling Kit |
| Item Dimensions | 13.81 x 4.88 x 8.06 inches |
| Item Highlight | Rough Gemstones, 4 Polishing Grits, Rock Polisher, Geology Science Kit, Rock Tumbling for Kids and Adults, Birthday Gift |
| Item Type Name | Rock Tumbler Kit – Hobby Edition |
| Item Weight | 5.1 pounds |
| Manufacturer | JMW Sales, Inc |
| Manufacturer Part Number | NGHOBBYTUMBLER |
| Manufacturer Warranty Description | No Warranty |
| Manufacturer recommended age | 8 years and up |
| Material Type | Plastic |
| Model Number | NGHOBBYTUMBLER |
| Number of Items | 1 |
| Number of Packs | 1 |
| Set Name | Hobby |
| Size | One Size |
| Sub Brand | National Geographic |
| Theme | Rock Tumbling |
| UPC | 816448020421 |
| Unit Count | 1 Count |
M**E
Genuine review after fully using it!
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!
J**R
Rock tumbler earned a A +++++
I've been without a rock tumbler for a yr now and decided on the national geographic model when I got I I found it easy to set up and it held quite a few medium size rocks (about 15) it's very quite we don't even hear it in the room it's a great value for your money and easy enough a child can use. Would recommend it to anyone. A+++++
E**S
Awesome tumbler, amazing customer service
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!!
D**A
Super Noisy, Requires constant supplies
It's a really cool tumbler, but it has to stay on for DAYS at a time, all day long. We don't have a garage, so it's extremely annoying and loud. You need 4 different types of special grit to be able to use it, it comes with one pouch of each, however you will have to be constantly buying supplies if you want to use it for more than a couple of runs. If you can get past the noise and constantly replenishing the grit then it might be worth it.
S**.
Needs voltage regulator and better final stage.
Needs a voltage regulator with it to slow the roll but with i think its better than more expensive brands. The final polish is worthless though. First 3 stages are ok but last polish needs to be 4000 and up.
N**E
Bought for 13 year old
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!
C**N
Good Value for Beginners
Great price and purchase, does make noise but not nearly as much as others we’ve had and actually works! Does take around 4 weeks per set of rocks minimum and you need more than one set of grit if you have a lot!
N**G
They are all turning out amazing. I would definitely recommend this product
I am on my last grit of my first round of rocks. I have to say that the results are beating my expectations. I found some rocks at a park and mixed them in with the ones that were shipped with the kit. I can't tell the difference between them. They are all turning out amazing. I would definitely recommend this product. I will say that a piece stopped working, but i contacted National Geographic and they fixed the issue immediately. I'll say that i will not fault a company for a faulty part, but it's how they handle it determines how the product is. Their customer service is amazing. They responded very quickly. Things you have to keep in mind when using a rock tumbler. This process normally takes years and years, i think a few weeks in a tumbler is just fine. It's all part of the process and fun. It is a little loud. I had to put it outside, but it sounds like rocks tumbling in water like you would expect. If you put in brittle rocks, they will fall apart. I'm not going to try to tumble limestone. I would imagine that sedimentary rocks would fall apart more easily. Good rocks in my area are quartz and granite. Finding the right type of rocks to tumble is half of the fun! I'll try to remember to add photos when it's all done.
M**D
ممتاز
ممتاز
D**I
Buy this product and enjoy your hobby but do not pay three time more on Amazon.
Excellent product and 100% results producer but now a days this product buy on Amazon is totally foolish idea because very very expensive compared to original cost in USA. Dear buyers don't buy this product.
P**K
Great quality
Does the job like professional tumbler
M**S
très bien
conforme à la description,notice claire et bien détaillée. Silencieux ! Rien à redire.
J**Z
PRODCUTO EN BUEN EDSTADO
PRODUCTO DE BUENA CALIDAD, EN EXCELENTE ESTADO A PRECIO BAJO, CON BUEN ASPECTO, MUY BIEN EMPAQUETADO Y PROTEJIDO
Trustpilot
2 months ago
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