The best rock tumbler of 2020
While the words "instant gratification" and "rock tumbling" may not fit in the same sentence, the hobby of rock collecting and polishing is still very satisfying. What begins as raw, unrefined rocks come out as beautiful, shiny stones in the end.
The key ingredient in this process is a product known as a rock tumbler. A rock tumbler holds one or two containers of rocks, abrasive grit, and water. As barrels rotate on the base, the grit slowly wears down and polishes the outer layer of the rocks.
While many rock tumbling sets include their own unpolished rock supply, users can still collect their own rocks in the field and add them to the tumbler for cleaning and polishing. The results can be used for decoration, display, or even jewelry.
We've taken a fresh look at our current short list of rock tumblers and have updated it based on industry trends and other factors. We have two returning favorites, along with a newcomer ideal for younger users.
Best rock tumblers of 2020
1. Discover with Dr. Cool's Hobby Rock Tumbler: This is a comprehensive kit, making it easy to operate right out of the box -- a big plus in our opinion.
2. National Geographic's Hobby Rock Tumbler Kit: For an entry-level rock tumbling kit, this selection includes an impressive assortment of rocks and jewelry-making accessories not always found in other sets.
3. Classic Crafts' NSI Rock Tumbler: A newcomer to our short list, but not to the rock tumbling world. It's considered a classic for a reason, and we like its affordable price point and sturdy design.
For full reviews of these products, scroll to the bottom.
What is a rock tumbler?
Many people like to collect interesting rocks they discover during hikes, camping trips, or other outdoor activities. However, these raw, unrefined stones don't have the luster or visual appeal of a polished gemstone. In order to achieve that look, you could wait a few thousand years for nature to do its work, or you can invest in a rock polishing machine known as a rock tumbler.
Rock tumblers are typically sold in one of two configurations: rotary or vibratory. A rotary model turns a barrel filled with raw stones, abrasive grit, and water. As the rocks tumble, they collide with each other and the abrasive grit. A vibratory model shakes the barrel but doesn't rotate it. This agitation works faster than rotation, but it doesn't smooth out the edges of the stones as well as a rotary machine.
Many rock tumbling kits include a sample bag of unpolished gemstones and other rocks, but users can also use rocks discovered in the field. Some types of rocks -- mainly those with porous or gritty surfaces -- don't do well in a tumbler, but those with hard, non-porous surfaces can yield surprisingly good results.
The rock tumbling process can take a month or longer, and the contents of the barrel need to be cleaned thoroughly when the grade of grit changes. It can also be a very noisy process, because the barrels need to be tumbled 24 hours a day for best results. This means users must find a location that's remote enough for noise reduction but still has an approved power source for the base.
Rock tumbler bases and barrels can be sold individually, but there are also comprehensive kits marketed toward a younger audience or casual hobbyists. Expect to pay at least $50 for a basic educational kit, and $300 or more for commercial-grade tumblers for gemstone polishing.
Q. What kinds of rocks are best for tumbling and polishing? I don't want to waste time and money on stones that can't be polished.
A. The best rocks for tumbling are hard and non-porous, such as agate, jasper, or other quartz. Porous rocks such as limestone gravel or sandstone are not good candidates, and softer stones can disintegrate during the tumbling process. Many kits include a premixed assortment of acceptable stones, or they can be purchased separately.
Q. How long does it take to go from raw unpolished rocks to the finished product?
A. The answer largely depends on the design and quality of the tumbler, but some vibratory models can produce polished stones in as little as one to two weeks.
In-depth reviews for best rock tumblers
Best of the best: Discover with Dr. Cool's Hobby Rock Tumbler
What we like: Uses a quieter rubber tumbling barrel. Works with other materials besides rocks. Includes four grades of grit. Timer is programmable, with an overheat sensor.
What we dislike: Polishing process can take longer than advertised. Frequent motor shut-offs reported by customers.
Best bang for your buck: National Geographic's Hobby Rock Tumbler Kit
What we like: Comprehensive kit includes real gemstones. Automatic shut-off function. Includes learning guide for STEM students. Contains additional jewelry-making material.
What we dislike: Instruction manual can be challenging to understand. Rocks may fracture or disintegrate during tumbling.
Choice 3: Classic Crafts' NSI Rock Tumbler
What we like: Intuitive design for children. Includes everything from grit to gemstones. Arrives with some jewelry settings, and upgrades are available. Affordable price point for comprehensive kit.
What we dislike: Plastic tumbler barrels are not durable. Very loud operation with a less robust motor.
Michael Pollick is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.
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