--- product_id: 316075421 title: "Blue Marble National Geographic Hobby Rock Tumbler Kit - Complete With Durable Tumbler, Rocks, Grit, And Patented Gemfoam Finishing Foam Polish, Educational Stem Science" brand: "blue marble" price: "€ 265.93" currency: EUR in_stock: true reviews_count: 5 category: "Blue Marble" url: https://www.desertcart.hr/products/316075421-blue-marble-national-geographic-hobby-rock-tumbler-kit-complete-durable store_origin: HR region: Croatia --- # Includes 9 gemstone types + GemFoam polisher Durable motor with time & speed control Leak-proof stainless steel barrel lid Blue Marble National Geographic Hobby Rock Tumbler Kit - Complete With Durable Tumbler, Rocks, Grit, And Patented Gemfoam Finishing Foam Polish, Educational Stem Science **Brand:** blue marble **Price:** € 265.93 **Availability:** ✅ In Stock ## Summary > 💎 Turn rough rocks into polished gems—and your downtime into a dazzling creative ritual! ## Quick Answers - **What is this?** Blue Marble National Geographic Hobby Rock Tumbler Kit - Complete With Durable Tumbler, Rocks, Grit, And Patented Gemfoam Finishing Foam Polish, Educational Stem Science by blue marble - **How much does it cost?** € 265.93 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/316075421-blue-marble-national-geographic-hobby-rock-tumbler-kit-complete-durable) ## Best For - blue marble enthusiasts ## Why This Product - Trusted blue marble brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **GemFoam magic:** Innovative reusable polishing foam delivers a dazzling shine that makes your stones Instagram-ready. - • **STEM meets style:** Educational and creative, this kit is perfect for professionals who want a hands-on escape that flexes both brain and craft. - • **Leak-proof luxury:** Stainless steel lid and improved barrel design ensure zero mess, zero stress—just pure tumbling joy. - • **All-in-one gem lab:** Comes with 1 lb of rough rocks, 4-stage grit, GemFoam polish, jewelry fastenings, and a strainer—everything you need to craft your own treasures. - • **Set it & forget it:** Robust motor with customizable time and speed settings lets you multitask while your gems get their glow-up. ## Overview The National Geographic Hobby Rock Tumbler Kit is a durable, all-inclusive rock tumbling system designed for ages 8 and up. Featuring a motor with adjustable time and speed controls, a leak-proof stainless steel barrel, and a unique GemFoam polishing foam, it transforms rough stones into beautifully polished gemstones. The kit includes one pound of rough rocks with nine gemstone varieties, tumbling grit, jewelry fastenings, and a strainer, making it an ideal STEM educational tool and creative outlet for beginners and hobbyists alike. ## Description CREATE YOUR OWN GEMSTONES - Rock tumbling is a hugely popular hobby for kids and adults! This robust 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. | ALL-IN-ONE TUMBLING KIT - You get one pound of rough rocks with nine different types of gemstones inside, five jewelry fastenings, tumbler grit, a strainer, and our innovative new GemFoam polishing foam. | 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! | SATISFACTION GUARANTEED - The National Geographic STEM series provides kids high-quality educational toys that are a whole lot of fun! If your experience is anything less than extraordinary, let us know so we can make it right for you. Review: Fun product and fantastic customer service! 👏 - This was very easy to use. As a first-time hobbyist, I've always wanted a rock tumbler, and the instructions and suggestions were very clear and easy to follow. I started making tumbled stone jewelry as gifts for friends, family, and the steady stream of caregivers and medical professionals my husband and I see on a daily basis. We are both disabled and I (despite my own issues) am my husband's main caregiver. Rock tumbling and making jewelry have become my escape from the daily chaos of our lives, my relaxation from my anxiety and chronic pain disorders, and something I can share that is uniquely mine. I've had this tumbler for a year now, and have enjoyed it immensely. Recently, however, the belt broke. Not a big deal but, since replacing the the broken belt with the included replacement belt, the unit was fine for a couple of weeks before it suddenly stopped one night in the middle of a 7-day tumble. I tried re-seating the canister and started it again, only for it to stop again (with all of the lights flashing) 30 seconds later. I looked online for any suggestions dealing with the issue, and came up with several possible things that could be causing the problem. I removed the belt and carefully cleaned the rotating pins. I cleaned between the base rollers and the buffer pads, and made sure no pet hair or dirt was built up anywhere that could be causing the stoppage. I removed the canister and removed half of the stones in case the weight was the issue. Despite all of this, the unit would not keep spinning, and kept "freezing " within minutes of restarting. Today is Monday 1/12/26. My husband is in the hospital due to an infection, and I am trying to catch up on some things I've been putting off due to time constraints. So, I called the customer service number listed on the box. Since the product was purchased from desertcart, I was able to supply the NatGeo/BlueMarble help desk associate with the date and order number of the unit. I was also able to give them the SEC/lot number information since I still have the box. I then found out that I was 13 days past the warranty/exchange period. Some companies would simply refuse any liability because it was past the warranty date, but not this one. After hearing my issue, what I had done to address the problem, and getting the pertinent information about my purchase of the item and the unit itself, they generously offered to replace the entire kit. I was definitely not expecting that, but it was a great surprise and absolutely made my day. In conclusion, the tumbler is great for a first-time or young user. The directions are easy to follow. The stones are beautiful, if a bit small, but perfect for jewelry or other things. There is an included booklet with sample pictures to help you identify your stones, which I found very helpful. Above all, NatGeo and Blue Marble are VERY responsive to any issues and actually stand behind their product, a rare find in today's marketplace. I highly recommend this product for young or beginner tumblers. It took me until my 57th birthday to get one, and I've been having a blast! Review: fonctionne bien - cadeau de noel pour mes parents qui aime faire des bijoux fantaisies. il me dise que le procédé est long mais que le résultat est bon. les pierres qu'ils ont ramassé eux même on perdu 50% de leur taille. ## Features - CREATE YOUR OWN GEMSTONES - Rock tumbling is a hugely popular hobby for kids and adults! This robust rock tumbler makes it fun and easy to turn rough - 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. - ALL-IN-ONE TUMBLING KIT - You get one pound of rough rocks with nine different types of gemstones inside, five jewelry fastenings, tumbler grit, a strainer, and our innovative new GemFoam polishing foam. - 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! ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B086Z6ZB7R | | Age Range Description | 8 years and up | | Age range (description) | 8 years and up | | Battery Description | Not required (mains powered) | | Best Sellers Rank | #62,272 in Kitchen ( See Top 100 in Kitchen ) #876 in Tumblers & Water Glasses | | Brand | Blue Marble | | Brand Name | Blue Marble | | Customer Reviews | 4.3 out of 5 stars 3,607 Reviews | | Educational Objective | Geology and Creative Thinking | | Included Components | 1/2lb rough rocks, 4 Stage Grit, Original GemFoam Polishing Media, toys | | Is Assembly Required | No | | Item Dimensions | 33.3 x 12.7 x 20.7 centimeters | | Item Type Name | toys | | Item Weight | 1.9 Kilograms | | Item dimensions L x W x H | 33.3 x 12.7 x 20.7 centimeters | | Item weight | 1.9 Kilograms | | Language | English | | Manufacturer | JMW Sales, Inc. | | Manufacturer Maximum Age (MONTHS) | 120 | | Manufacturer Minimum Age (MONTHS) | 12.0 | | Manufacturer Part Number | NGHOBBYTUMBLER2 | | Manufacturer Warranty Description | No Warranty | | Material Type | Cotton | | Model Number | NGHOBBYTUMBLER2 | | Set Name | Hobby Rock Tumbler Kit | | Size | One Size | | Sub Brand | National Geographic | | Theme | Geology | | UPC | 816448028830 | | Unit Count | 1 Count | ## Product Details - **Age range (description):** 8 years and up - **Brand:** Blue Marble - **Item dimensions L x W x H:** 33.3 x 12.7 x 20.7 centimeters - **Size:** One Size - **Theme:** Geology ## Images ![Blue Marble National Geographic Hobby Rock Tumbler Kit - Complete With Durable Tumbler, Rocks, Grit, And Patented Gemfoam Finishing Foam Polish, Educational Stem Science - Image 1](https://m.media-amazon.com/images/I/915PyUpEsJL.jpg) ## Questions & Answers **Q: What is the power consumption of this unit over a week of continuous use? (in usa on 110v). thank you.** A: This takes .3 Amps, so (watts = amps x volts) OR watts = .3 x 110 which equals33 watts. Now for one week would equal 33 watts x 7 days x 24 hours =5544 watts or 5.54 kilowatts for one week.At $.16 per kilowatt it comes to $.89 per week. **Q: What the difference between this and the starter kit?** A: There are two main differences:The Hobby Rock Tumbler has a rubber tumbling barrel with a stainless steel cap, which reduces noise and is more durable. The Starter Kit Rock Tumbler has a plastic barrel. The Hobby Rock Tumbler also has a keypad for setting the number of days you would like it to tumble, where as the Starter Kit Rock Tumbler's setting options are on/off. Thank you for your inquiry. **Q: What pound tumbler is this product?** A: Dearest National Geographic.... why would you only send 1# of rocks with a two pound tumbler? **Q: Can i buy extra grit without the rocks. we have many rocks from "mining" gemstones that i would love to polish. what do you recommend?** A: I recommend you follow the rock tumbler hobbiest MIchigan Rocks on Youtube. He's a good wealth of information for anyone getting into rock tumblers. He and other's mention that the polish from National Geographic is not good. I would go with rock tumbler polish offered by Polly Plastics. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Fun product and fantastic customer service! 👏 *by J***. on 12 January 2026* This was very easy to use. As a first-time hobbyist, I've always wanted a rock tumbler, and the instructions and suggestions were very clear and easy to follow. I started making tumbled stone jewelry as gifts for friends, family, and the steady stream of caregivers and medical professionals my husband and I see on a daily basis. We are both disabled and I (despite my own issues) am my husband's main caregiver. Rock tumbling and making jewelry have become my escape from the daily chaos of our lives, my relaxation from my anxiety and chronic pain disorders, and something I can share that is uniquely mine. I've had this tumbler for a year now, and have enjoyed it immensely. Recently, however, the belt broke. Not a big deal but, since replacing the the broken belt with the included replacement belt, the unit was fine for a couple of weeks before it suddenly stopped one night in the middle of a 7-day tumble. I tried re-seating the canister and started it again, only for it to stop again (with all of the lights flashing) 30 seconds later. I looked online for any suggestions dealing with the issue, and came up with several possible things that could be causing the problem. I removed the belt and carefully cleaned the rotating pins. I cleaned between the base rollers and the buffer pads, and made sure no pet hair or dirt was built up anywhere that could be causing the stoppage. I removed the canister and removed half of the stones in case the weight was the issue. Despite all of this, the unit would not keep spinning, and kept "freezing " within minutes of restarting. Today is Monday 1/12/26. My husband is in the hospital due to an infection, and I am trying to catch up on some things I've been putting off due to time constraints. So, I called the customer service number listed on the box. Since the product was purchased from Amazon, I was able to supply the NatGeo/BlueMarble help desk associate with the date and order number of the unit. I was also able to give them the SEC/lot number information since I still have the box. I then found out that I was 13 days past the warranty/exchange period. Some companies would simply refuse any liability because it was past the warranty date, but not this one. After hearing my issue, what I had done to address the problem, and getting the pertinent information about my purchase of the item and the unit itself, they generously offered to replace the entire kit. I was definitely not expecting that, but it was a great surprise and absolutely made my day. In conclusion, the tumbler is great for a first-time or young user. The directions are easy to follow. The stones are beautiful, if a bit small, but perfect for jewelry or other things. There is an included booklet with sample pictures to help you identify your stones, which I found very helpful. Above all, NatGeo and Blue Marble are VERY responsive to any issues and actually stand behind their product, a rare find in today's marketplace. I highly recommend this product for young or beginner tumblers. It took me until my 57th birthday to get one, and I've been having a blast! ### ⭐⭐⭐⭐⭐ fonctionne bien *by C***L on 28 March 2023* cadeau de noel pour mes parents qui aime faire des bijoux fantaisies. il me dise que le procédé est long mais que le résultat est bon. les pierres qu'ils ont ramassé eux même on perdu 50% de leur taille. ### ⭐⭐⭐⭐⭐ Oj *by J***N on 15 April 2026* Ok ## Frequently Bought Together - NATIONAL GEOGRAPHIC Hobby Rock Tumbler Kit – Durable Leak-Proof Rock Polisher with 7-Day Timer – Complete Rock Tumbling Kit – Geology Hobby for Kids, Educational STEM Science Kit, Rock Collection - Blue Marble National Geographic Rock Tumbler Grit and Polish Refill Kit - Tumbling Grit Media, Polish Up to 20 lbs. of Rocks, Works with Any Rock Polisher, Rock Tumbler Supplies - NATIONAL GEOGRAPHIC Rock Tumbler Refill Kit – 1Lb. Gemstones and Rocks for Tumbling including Unpolished Amethyst and Quartz – Rock Tumbler Supplies include Rock Tumbler Grit and Jewelry Accessories --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.hr/products/316075421-blue-marble-national-geographic-hobby-rock-tumbler-kit-complete-durable](https://www.desertcart.hr/products/316075421-blue-marble-national-geographic-hobby-rock-tumbler-kit-complete-durable) --- *Product available on Desertcart Croatia* *Store origin: HR* *Last updated: 2026-07-08*