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Blue Marble

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

    • Based on 4,621 reviews
Condition: New
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Availability: Only 5 left in stock, order soon!
Fulfilled by Amazon
Arrives Sunday, Mar 16
Order within 13 hours and 16 minutes
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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!
  • HIGH-QUALITY EDUCATIONAL TOYS - We're proud to make the highest quality hands-on science toys, and all our products are backed by exceptional service. If your experience is less than stellar, let us know and we'll make things right!

Product Dimensions: 12.76 x 10.31 x 6.69 inches


Item Weight: 8.14 pounds


Country of Origin: China


Item model number: NGTUMBLER3LB


Manufacturer recommended age: 8 years and up


Is Discontinued By Manufacturer: No


Release date: July 5, 2023


Manufacturer: JMW Sales, Inc.


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, Mar 16

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.

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Top Amazon Reviews

    • Excellent Tumbler with Insufficient Supplies
Review Image by Michael Allen Michael Allen
Review Image by Michael Allen Michael Allen
Review Image by Michael Allen Michael Allen
Review Image by Michael Allen Michael Allen
Review Image by Michael Allen Michael Allen
Review Image by Michael Allen Michael Allen
The media could not be loaded. 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! ... show more
Reviewed in the United States on June 15, 2021 by Michael Allen Michael Allen
    • Use-ability and Durability for business/professional use!
Review Image by David J Ross David J Ross
This is my first review on Amazon. I'm compelled to write this because I have been through so many rock tumblers as I tumble rock 24/7/365. Lortone are supposed to be the best and they are priced as such but the failure rates are just to high. This machine is more durable, 3X cheaper, easier to service (I haven't needed to service any of them yet) and work like a horse. They use lower power, they have built in timers so you don't need to remember when you started and you can spin the barrels 3X faster than a typical tumbler. I have 3 of them and I love them. Best value out there if you only got the tumbler and the barrel! You will need to buy more grit supplies if you want to tumble more than 1 batch, but there is enough in the kit to get started. ... show more
Reviewed in the United States on September 10, 2024 by David J Ross David J Ross
    • Great starter drum that works well!
The kit has every thing you need to polish stones. The drum and roller and well built and hold up to use. I have a couple of these sets and like them a lot. The drum does not leak and is easy to load and use. Comes with grit to get you started. A quick search for polishing grit on Amazon will help keep you supplied. ... show more
Reviewed in the United States on December 17, 2024 by William
    • Worked for 2 months…got a new one
Got this tumbler 2 months ago and was working fine until today. Completely stopped working. Motor won’t turn on at all. Has been gently used in an adult only household so no reason for it to break. Tried trouble shooting steps but nothing. I contacted Nat Geo customer service and I’ll guess I’ll see what they say when they get back to me. And edit this review based on that EDIT - I spoke to Nat Geo and they said the likely culprit is faulty weight sensor, which apparently is a problem with these tumblers. They sent me a new one free. I’m grateful for the customer service and the new matching but if I had realized this make/model had this issue I wouldn’t have gotten it in the first place. I’m hoping this second one lasts longer than the first one. ... show more
Reviewed in the United States on December 15, 2024 by Rachel
    • Top tier customer service!
This tumbler works great and with some patience it creates some really nicely polished stones. If you ever need customer assistance they are the best I have ever experienced. Cannot rave enough about Bluemarble customer service. AA++ all the way
Reviewed in the United States on February 18, 2025 by B. Bailey

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