---
product_id: 82423825
title: "National Geographic Rock Tumbler Refill Kit with 3 Lbs. Rough Gems"
brand: "blue marble"
price: "¥18399"
currency: JPY
in_stock: true
category: "Blue Marble"
url: https://www.desertcart.jp/products/82423825-national-geographic-rock-tumbler-refill-kit-with-3-lbs-rough
store_origin: JP
region: Japan
---

# 3 lbs. Rough Gemstones STEM Educational Focus 4-Stage Grit Polishing System National Geographic Rock Tumbler Refill Kit with 3 Lbs. Rough Gems

**Brand:** blue marble
**Price:** ¥18399
**Availability:** ✅ In Stock

## Summary

> 💎 Polish your passion, rock your world!

## Quick Answers

- **What is this?** National Geographic Rock Tumbler Refill Kit with 3 Lbs. Rough Gems by blue marble
- **How much does it cost?** ¥18399 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/82423825-national-geographic-rock-tumbler-refill-kit-with-3-lbs-rough)

## 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

- • **Award-Winning Quality:** From Blue Marble, Toy Association’s Toy of the Year winner, ensuring premium craftsmanship and educational value.
- • **Gemstone Variety Galore:** Includes 3 pounds of diverse rough gems like Amethyst and Quartz for endless creative polishing.
- • **STEM Learning Meets Fun:** Perfect for ages 8+, this kit blends hands-on science with artistic expression, making it a must-have for curious minds.
- • **Ready for Jewelry Crafting:** Includes essential jewelry accessories so you can turn your polished gems into wearable art and impress your social circle.
- • **Precision 4-Stage Grit System:** Achieve museum-quality shine with a proven multi-step polishing process that transforms raw stones into dazzling treasures.

## Overview

The National Geographic Rock Tumbler Refill Kit offers 3 pounds of rough gemstones including Amethyst and Quartz, paired with a 4-stage grit polishing system designed for ages 8 and up. Developed by Blue Marble, an award-winning brand, this STEM-focused kit delivers an immersive educational experience that transforms raw stones into polished gems ready for jewelry crafting—all without batteries. Elevate your creative hobbies with this premium, hands-on rock tumbling refill set.

## Description

Buy National Geographic Rock Tumbler Refill Kit with 3 Lbs. Rough Gems | 3 Lbs. Rough Gemstones, Amethyst and Quartz, 4-Stage Grit, Jewelry Accessories, Rock Polishing Supplies: Rock Tumblers - desertcart.com ✓ FREE DELIVERY possible on eligible purchases

## Features

- 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!

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07H7WFWYT |
| Age Range Description | 8 years and up |
| Best Sellers Rank | #69,903 in Toys & Games ( See Top 100 in Toys & Games ) #24 in Kids' Rock Tumblers |
| Brand Name | Blue Marble |
| Color | Multicolor |
| Customer Reviews | 4.7 4.7 out of 5 stars (2,412) |
| Educational Objective | STEM |
| Global Trade Identification Number | 00816448025914 |
| Included Components | 3 Pounds of rough Gemstones |
| Item Dimensions | 5.37 x 5.31 x 5.44 inches |
| Item Highlight | 3 Lbs. Rough Gemstones, Amethyst and Quartz, 4-Stage Grit, Jewelry Accessories, Rock Polishing Supplies |
| Item Type Name | Rock Tumbler Mega Refill Kit - 3lbs Gemstones of 9 Varieties |
| Item Weight | 1.36 kg |
| Manufacturer | JMW Sales, Inc. |
| Manufacturer Part Number | NGGEMREFILLMEGA |
| Manufacturer Warranty Description | We're proud to make the highest quality products which are backed by exceptional service. |
| Manufacturer recommended age | 8 years and up |
| Material Type | Plastic |
| Model Number | NGGEMREFILLMEGA |
| Operation Mode | Manual |
| Set Name | National Geographic Rock Tumbler Refill Kit |
| Size | 3 Pounds |
| Sub Brand | National Geographic |
| Supported Battery Types | No batteries required |
| Theme | Gemstones |
| UPC | 816448025914 |
| Unit Count | 1 Count |

## Product Details

- **Brand:** Blue Marble
- **Age Range (Description):** Kid
- **Color:** Multicolor
- **Theme:** Geology
- **Item dimensions L x W x H:** 5.37 x 5.31 x 5.44 inches

## Images

![National Geographic Rock Tumbler Refill Kit with 3 Lbs. Rough Gems - Image 1](https://m.media-amazon.com/images/I/A1+omj2TEGL.jpg)

## Available Options

This product comes in different **Style** options.

## Questions & Answers

**Q: how many pounds of rocks can the grit tumble**
A: The instructions for the Tumbler does not give a specific weight. It recommends not filling the Tumbler barrel more than 1/2 to 2/3 full. If you overfill the Tumbler, the built-in sensor will automatically protect the motor inside by turning the Tumbler off. It further recommends if this happens you should remove some of the rocks.The grit to be used in the Tumbler comes in premeasured packets for the Tumbler size itself.  I hope this helps.

**Q: Are these uncut gemstones sourced ethically? Can you provide evidence if so?**
A: I only buy from reliable dealers. I buy a lot from National Geographic through Amazon. I’m not sure where I can find proof. I’m sorry I couldn’t give you a better answer.

**Q: Where were the rock mined?**
A: I think they were mined in Madagascar.

**Q: Does this kit list the Mohs hardness of the different stones? I know you're not supposed to polish rocks with different hardness together**
A: No, there is not a Mohs hardness scale included in this kit, but you should be able to locate a copy online.

## Frequently Bought Together

- National Geographic Rock Tumbler Refill Kit – 3 lbs. of Rough Gemstones and Rocks for Tumbling Including Amethyst and Quartz – Rock Tumbler Supplies Include Rock Tumbler Grit and Jewelry Accessories
- 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
- 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

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**Shop now:** [https://www.desertcart.jp/products/82423825-national-geographic-rock-tumbler-refill-kit-with-3-lbs-rough](https://www.desertcart.jp/products/82423825-national-geographic-rock-tumbler-refill-kit-with-3-lbs-rough)

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-09-17*