National Geographic Rock Tumbler Kit - 3 Lb. Extra Large Capacity Barrel with 3-Speed Motor & 9-Day Timer, Kit Includes Rocks for Tumbling and Rock Polisher Grit, Rock Tumbler for Adults and Kids
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Availability:
Only 5 left in stock, order soon!
Arrives
Friday, Jul 31
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Style: 3Lb Barrel
Features
- CREATE YOUR OWN GEMSTONES - Rock tumbling is a hugely popular hobby for kids and adults! This professional rock tumbler makes it fun and easy to turn rough rocks into beautifully polished gemstones, thanks to its simple operation and durable design.
- A TUMBLER THAT'S MADE TO LAST - The durable motor has time and speed control settings so you can set it, and forget it. An improved, leak-proof barrel features a stainless-steel lid is 75% quieter overall than plastic tumbler barrels.
- INCLUDES 3 LBS. OF ROCKS & MORE - This tumbling kit comes with everything you need: 3 lbs. of raw rocks with 9 types of gemstones, 5 jewelry fastenings, grit, strainer & GemFoam for a dazzling shine!
- USE GEMFOAM FOR DAZZLING RESULTS - This rock tumbler kit stands apart from others thanks to our new, reusable GemFoam rock polisher! Add GemFoam and water to the barrel after your final tumbling stage and your gems will have incredible shine!
- AWARD-WINNING PRODUCTS - Blue Marble, winner of the Toy Association's prestigious Toy of the Year Award, proudly develops products that foster education, imagination, and creativity, with a U.S. support team to ensure a stellar experience!
Brand Name: Blue Marble
Age Range Description: 8 years and up
Educational Objective: STEM, Concept Development Skills, Hand-Eye Coordination, Critical Thinking, Reasoning Exploratory Skills
Sub Brand: National Geographic
Set Name: Set
Manufacturer Maximum Age (MONTHS): 1188.0
UPC: 816448028694
Manufacturer Minimum Age (MONTHS): 96
Model Number: NGTUMBLER3LB
Manufacturer Part Number: NGTUMBLER3LB
Manufacturer: JMW Sales, Inc.
Item Type Name: Rock Tumbler Kit - 3 Lb. Extra Large Capacity Barrel
Unit Count: 1.0 Count
Included Components: Complete Rock Tumbler Kit, 3lb Assorted Rough Gems, 4 Stages of Polishing Grit,5 Jewelry Settings,GemFoam
Theme: Geology
Is Assembly Required: No
Material Type: Plastic, Stainless Steel
Size: One Size
Item Dimensions: 12.76 x 10.31 x 6.69 inches
Item Weight: 3.7 Kilograms
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Friday, Jul 31
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Had one of these as a kid. Great size works like a tank!
Reviewed in the United States on April 15, 2026 by Dalton Goldman
I started using the National Geographic 3 lb. tumbler in March of 2021. I’m new to rock tumbling, so as I’ve been getting started, I’ve been studying best practices in hopes of maximizing my results. *** Edit *** I like this tumbler so much, I bought a second one. ***/Edit *** This tumbler is extremely well-made. The base, which includes the motor & control panel, is very sturdy. The barrel is exceptional, in that it is larger than other 3 lb. capacity tumbler barrels, and has a very effective sealing mechanism to prevent leaks. There is an extra drive belt included, for when the original belt wears out, or breaks. The overall operation of this unit is smooth, with minimal vibrations. Most of the sound comes from the motor, as the material of the barrel tends to absorb the sound of the rocks tumbling around inside. On speed 3 (the fastest speed), I measured 65 dB right next to the tumbler. Since a rock tumbler has to run 24 hrs. a day, seven days a week, it’s advisable to have it in a garage or basement, so you don’t have to hear it running. While it doesn’t vibrate excessively during use, there is enough vibration to cause it to creep around on a smooth surface. Best to set it on a rubber pad, or otherwise block the base, so it doesn’t creep right over the edge of your work bench. There are two features to this tumbler that make it unique. First, it has 3 speeds, and even the slowest speed is faster than most other tumblers. This must be taken into account when you are determining how best to fill the barrel & how long to run each tumbling cycle. The second unique feature is the shape of the barrel, which is less deep, but larger diameter than other tumbler barrels. The internal volume is actually larger than that of other 3 lb. tumblers. This allows you to put more rocks in each cycle, with more of the weight of the rocks concentrated in a smaller area & tends to increase the efficiency of the grinding action. Faster speeds & more efficient grinding cause the rocks to hit each other more often, which will shape and smooth them in a shorter period of time than with other tumblers. But it also may require you to cushion more fragile rocks (such as feldspar) with tumbling media (such as ceramic pellets) to prevent bruising. Consider the price of this item to be for just the tumbler, with the rocks & grit included for free. The rocks you get are literally a “mixed bag” of all different types & hardnesses. One of the cardinal rules of rock tumbling is to only tumble rocks of the same hardness & durability together in the same barrel. So you don’t want to mix agates with feldspar, for example. Once you separate the included rocks by type, you will find that there aren’t nearly enough rocks to fill the barrel with similar rocks. Best to order 3-5 lbs. of a single type of rocks (search for “tumbling rough” online) so you can fill the barrel correctly for the best results. After a bit of experimentation, I have found that this tumbler produces the best results when the barrel is 3/4 full. This is about 3 lbs., although the weight will depend on the density of the rocks in your barrel. The main consideration should be where the top of the rocks are, compared to the bottom of the lid. By measuring the depth of the barrel, you can easily make a gauge that will represent the correct amount of space to leave at the top. Too many rocks in the barrel will prevent them from tumbling freely, but too few will just bounce around in the barrel, instead of sliding & grinding against each other. If your barrel is too heavy, it will cause the motor to shut down & you will have to follow the steps in the instruction manual to get it working again. I have routinely filled the barrel with 3 lbs. of dry rocks (plus water & grit) without having it shut down. I have also found that I get the best results when I include some ceramic tumbling media to fill the gaps between the rocks (this helps to carry the grit for more efficient grinding & also to cushion the rocks.) The included grit & polish packets are insufficient to produce good results. Buy some bulk grit & polish from a rock shop (there are several online.) You will want 60/90 Silicon Carbide for stage 1 (about 4 tablespoons per load.) You will use much more of this than any other grit, as stage 1 can take several cycles to shape hard rocks, such as agate & jasper. Stage 2 requires 120/220 Silicon Carbide (about 4 tablespoons per load.) You will probably need to run one or two cycles in stage 2, until the rocks are smooth. Stage 3 requires 500 grit (either Silicon Carbide, or Aluminum Oxide) - about 4 tablespoons per load. This stage will probably only take 1 cycle & the rocks will start to show a slight gloss & feel really smooth. Stage 4 requires Aluminum Oxide polish (about 3 tablespoons.) This will generally be a single cycle (until the rocks are shiny when dry.) I have never used the included foam cubes. Instead, I run a burnishing cycle using 4 tablespoons of borax powder & a squirt of Dawn dish soap. (All stages require just enough water to almost cover the rocks.) I run stage 1 on speed 3 (fastest) in 4-day cycles. Empty the barrel, rinse the rocks into a bucket, & examine them. If all of the edges are rounded, set the rock aside for stage 2. If there are still rough edges or large pits, you will need to put the rock back into stage 1. Because most of the grinding happens in stage 1, you will have to add more rocks in each cycle to keep the barrel at 3/4 full. This requires a large enough supply of rocks to keep feeding the barrel. Six pounds of rough might yield three pounds of polished stones. When your pile for stage 2 is large enough, you can proceed. This may take a month or more. Once you move on to stage 2, things move faster. I run stages 2-4 at speed 1 (slowest) in 7 day cycles. Use the same process as described above to sort your rocks. When you finish stage 2, there should be no rough spots (usually 7-14 days.) When you finish stage 3, the rocks should feel very smooth & maybe slightly glossy (about 7 days.) If your rocks still aren’t shiny after 10 days in stage 4 (polish), you might consider trying another type of polish (such as Cerium Oxide, or Tin Oxide) for an additional 4 days. This is an excellent rock tumbler that comes with insufficient supplies. My advice is to buy the tumbler, throw out the grit & polish, order your rough rocks and grit/polish from a rock shop, and consider the included rocks as a bonus. There are many excellent resources available online, including YouTube videos & a forum called “Rock Tumbling Hobby.” If you are considering buying a rock tumbler, you should check these out. My most valuable resource has been a book called “Modern Rock Tumbling”, by Steve Hart. It covers everything involved in the tumbling process, with excellent advice for how to get good results. *** Edit *** The motor went out on my tumbler, but I e-mailed [email protected] with a copy of my receipt, and explained the problem. They replied within the hour to tell me that they were sending me a new tumbler as a replacement (no charge.) The new tumbler arrived in two days. Superior customer service!
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Reviewed in the United States on June 15, 2021 Reviewed in the United States on June 15, 2021 by Michael Allen
I purchased my first Nat Geo 3 Lb Professional tumbler in January. I liked it so much I now have several running and I run them every day. They're easy to fill, clean and are relatively quiet. I especially love the rubber barrel that cushions the rocks while they tumble and are much quieter than plastic or polyethylene counterparts. I've had very nice results polishing many different types of rocks and Mohs hardness levels. It's certainly easy enough to use that kids could enjoy this tumbler but it's also of high enough quality for adult enthusiasts. The first tumbler I purchased stopped running recently and after unplugging it and plugging it back in, it resumed running but much slower and would no longer run on 3 speeds. I sent an email to Nat Geo customer service (on a Sunday afternoon) asking if they could help and got an immediate response. The rep asked for proof of purchase and because it had been purchased within the last year, they sent me a new tumbler at no cost. It arrived THE SAME DAY! On a Sunday no less. That's what I call standing behind your product and excellent customer service. Very impressed!
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Reviewed in the United States on October 21, 2024 by Amazon Customer
I'm an adult hobbyist, not a kid or a parent - and this machine seems like a valid option for anyone - so far - I am writing this review the night after receiving it and will update if anything goes horribly wrong. I live near a river and collect rocks, and have wanted a tumbler for a while, but the startup cost seemed a little steep to me however, this kit is affordable for what it contains. The machine is sturdy, with a good sized rubber barrel. I fit about 25-30 rocks of varying size in mine for it's first tumble. It makes noise obviously, but not as much as I thought it would. It kind of sounds like a washing machine. Except, full or rocks. The setup is very easy, there is no assembly required, you literally plug it in, set how many days you want it to run for, and how fast. The instructions provided tell you how long and how fast to do each stage. The rubber lid beneath the metal screw-on top was a little difficult to get off at first, but I'm assuming that is because it was literally vacuum sealed - and it isn't something you want leaking. The kit came with a few tacky jewelry fixtures which might be relevant for a 7 year old but were nothing impressive. A few bags of rocks are also provided - but honestly only about half of mine were viable. Some of them looked cool, but many of the "rocks" were just chipped off pieces or flakes of larger chunks, and were probably too brittle to survive tumbling. Breakage can happen, and rocks shrink a lot with every cycle, so something the size of a quarter might be the size of a penny when it is done. A lot of the rocks I threw in my first batch were from digging around in parks and on river banks. Some notes: - I have no idea if the "Gem Foam" is worth it. I follow several people on social media who tumble a lot, and I have never seen any of them use foam media to polish their rocks. It may just be an unnecessary addition that NatGeo is using to try to make their product seem different. - Additionally, many of the people I follow as well as some of the other customers who purchased this item complain that their rocks do not get shiny. I have read that washing out the barrel and doing a short (3-5 hours) cycle with the rocks and some ivory soap shavings to clean everything between grit stages helps the rocks achieve a good shine. - Also, I have discovered that the polish (the final step) NatGeo provides in this kit and others they manufacture, is...unsatisfactory. A good brand to go with is Polly Plastics for better polish and grit refills. - I have also read that ceramic media can help rocks to tumble better in less time. I do not have any myself but I believe it is something I will try in the future. Tips? - You are going to also want to buy a big cooking strainer and dedicate it to your rocks to rinse them off after each cycle - Don't wash the grit down any sink or tub because it can clog your pipes when it hardens
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Reviewed in the United States on February 23, 2022 by Absolem
The rock tumbler ran great for 4 weeks, now it has an E1 error even when no barrel is used. (Just the base running). Contacted the manufacturer and they sent a replacement the next day. This is a fine rock tumbler for a beginner. (We are)
Reviewed in the United States on November 13, 2025 by Sarah S
EDIT 08/29/21 - Still going strong with almost constant use. We found that the rocks aren't polished quite to a glass like finish. After watching some youtube videos we found a professional who tried using this very tumbler... he was skeptical at first but then he said with "modifications" to the process you could get better results. Some of those modifications include running it only on the slowest speed setting, using more grit than they provide (buying extra in other words) and running each stage several times until you get the results you want. He also advised that you could buy a finer final grit beyond what the kit comes with. Using the machine as is with their grit will get you decent results though... just thought I'd throw this out as a further suggestion. I don't regret this purchase at all. ORIGINAL REVIEW I felt daunted when I got everything out but it actually is easy to do. I was also SHOCKED how smooth the rocks were after stage 1 (that is the rock picture in my review just after stage 1). We had 4 more stages to go at that point! I was also shocked at how small the rocks got by stage 4 - many were just totally disintegrated - many others were so tiny they wouldn't be good for much. Next time I'll start with bigger rocks for sure. Pro Tips - (and they say this on the directions but do listen to them!) DO NOT DUMP THE WATER DOWN YOUR SINK. It will destroy it. Dump it on the street outside your home or somewhere you don't care about. It's hard to get the rock sludge cleaned out of things It really sticks. Even after a few rain showers the street where I dumped it still has the rock residue stuck to the pavement. It's like glue. As I said above, start with the biggest rocks you can, they REALLY shrink down after that first cycle. We set ours up to go in our garage, and that seems optimal. It's sorta noisy. Not awful, but loud enough you would not want this in your home constantly listening to it drone on and on!
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Reviewed in the United States on July 6, 2021 Reviewed in the United States on July 6, 2021 by JKT
It literally is as easy as finding rocks on the ground, filling this thing up 2/3 full, adding some water just to cover the top of the rocks, sprinkle a little bit of powder, drop it on the machine, set the speed and days, and good to go. If you don't want to look for your own rocks that's okay because they give you a bag of red jasper, tigers eye, citrine, quartz, rose quartz, amethyst, and more to tumble for your first batch. The stones they gave looked like they were cut off from chunks used to make jewelry, but nonetheless were amazing to receive. The quality of the rubber barrel is amazing. It is thick and durable feeling. It also really dampens the sound that can be generated from most rock tumblers. The machine has three speeds and can go for the nine days. The back bar has a belt that goes to a motor that runs it. When you put the barrel of rocks on it stops vibrating because of the weight holding it down. I still placed a towel under it to further dampen the noise and all I hear is rocks sloshing and a faint motor hum. If you want to dampen sound further you can put a 5 gallon bucket over it and you won't hear pretty much anything. But I wouldn't want to do that to this machine. It's somewhat a thing of beauty because you know it's contents. And slight entertainment watching it tumble knowing again that you're stones a month from now will be polished and amazing. I mean you can't see the stones tumble because it's not a clear case, but that lets you use your imagination on the stones you put in. How much are they going to get worn down? What designs and patterns will they reveal? How shiny are they going to be? Patience is rewarded with this rock tumbler. I've had it for almost a month and have them on stage four, final polish. They have about a week to go and then they came with some gemfoam cubes for another few days polish. But each time I've pulled them out and rinse them off outside in the yard they look more and more amazing. Do not put any rock grit down your drains. It's a whole bunch of chips and tiny bits of rock that if you pour down your drain will get stuck in the pipes u bend because they're heavier than water. This is not an instant gratification machine. This will take minimum a month if you do a four-stage batch one week per stage. TLDR - large barrel size, dual clamp lid, starter kit comes with stones grit and jewelry stuff, quietest tumbler, just add water.
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Reviewed in the United States on May 31, 2024 by MJ
So durable and well made! Came with a lot of extras. It's pretty quiet as well. Have not had one problem yet with it and I've ran it and ran it and ran it . Haven't had to even replace the belt yet. No problem recommending this to anyone who is just getting started or who just wants to tumble some smaller stones! Quality everything all the way around this thing! And can't beat that kind of quality for that price! HIGHLY recommend!!
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Reviewed in the United States on May 6, 2026 by Amazon Customer