National Geographic Rock Tumbler Deluxe Series: Geology Kit for Grades 2-10 with Activity Guide

A: Thank you for your question. We’re so sorry to hear that your tumbler arrived defective—this is certainly not the experience we want for our customers. For the fastest resolution, we recommend reaching out to the manufacturer directly. Their contact information can be found on the box and on the back of the user manual. They’ll be happy to help make things right!

A: Thank you for your question. I’m sorry to hear your kit was missing the “Step 1” grit. This four-stage silicon carbide grit for rock tumbling systems is the ideal way to give rough rocks a smooth, polished look. The first rock polishing stage smooths rough edges and provides initial shaping. The second stage smooths the rock surfaces even more. The third stage provides a strong pre-polish, followed by the fourth stage which completes the grit polishing process. Because each step is designed to polish the rocks in a different way, we would be happy to send you a “Step 1” grit to maximize your rock tumbling experience.

A: Thank you for your question! Tumbled Tiger’s Eye does not contain raw, fibrous crocidolite. During the natural formation process, the crocidolite (a type of asbestos) is replaced by quartz through a mineral transformation called pseudomorphism, which stabilizes the material. Once fully replaced by quartz, the fibers are encapsulated, making the stone safe to handle and tumble. When tumbling Tiger’s Eye in a rock tumbler, the process smooths the surface but does not release airborne asbestos because the mineral structure has already changed. However, as with all lapidary work, it’s always a good practice to wet sand or polish to minimize dust and work in a well-ventilated area. Let us know if you have any other questions!

A: Thank you for your question. In a 1-pound rock tumbler barrel, the recommended maximum rock size is about ½ inch to 1.5 inches in diameter. For the best tumbling results, it's ideal to have a mix of small and medium-sized rocks, ensuring there’s enough space for movement and grit circulation. A single larger rock (around 2-3 inch) may fit, but it could limit the effectiveness of the tumbling process. Always aim for a well-balanced load to achieve smooth, polished results!

A: Thank you for your question. The National Geographic rock tumbler (when running) is ~75 decibels.

A: Thank you for your question. The exterior of the barrel is a hard plastic while the inside of the barrel is rubberized.

A: Thank you for your question. Yes, you can use our rock tumbler to tumble glass, though there are a few considerations to keep in mind: 1. Type of Glass: Sea glass, broken bottle glass, or any glass items you want to polish can work well in a rock tumbler. Softer, thin glass may break, so thicker pieces are better. 2. Cycle Time: Tumbling glass can take less time than tumbling rocks. Often, two to four days per grit stage is sufficient, though this depends on the desired finish. 3. Sharp glass: Glass with sharp edges can cut the barrel, so choose pieces that are not jagged