If you're looking to teach your young explorers about rocks and crystals, this National Geographic's hobby tumbler is an ideal place to start.

The best science kits for kids are an ideal way to connect adults and kids alike through the magic of education, and there are plenty of options - we even made a list. With microscopes, assembly kits, and much more, there's one you may have missed from your tour of wonders - geology.

The best rock tumblers (opens in new tab) can help build your child's increase in geology, and this deal at Amazon can help you do so at a bargain price. Right now, you can get the National Geographic Professional Rock Tumbler for just $84.99 (opens in new tab) at Amazon. This $15 discount isn't massive, but it is the cheapest we've seen this set so if you're on the fence, now is a great time to buy.

National Geographic Professional Rock Tumbler - Was $99.99, now $85.39 at Amazon (opens in new tab)

Save $15 on this STEM hobby kit, which includes everything you need to make your own gemstones.

The National Geographic Professional Rock Tumbler includes everything you need to get started with, well, rock tumbling. Inside the box you'll find four polishing grits, a sifter, 5 jewelry fastenings, a 1 lb. bag of raw rocks with 9 different types of gemstones, and GemFoam to help enhance the shine on your finished rocks.

Alongside that, you'll find the tumbler itself, which is made of high-quality materials and a learning guide to explain how gemstones are found, refined, and traded.

The manufacturer notes that the motor will run for years, no doubt aided by an automatic shutoff timer.

It's not just educational, either -- the National Geographic Professional Rock Tumbler is ideal for putting together homemade jewelry, with included fastenings for creative hands to use once the rocks are polished.

Customer reviews are positive (opens in new tab), too, with many praising its ability to polish rocks -- as long as you have the patience for it. Some have also noted the noise that the machine makes, so buyer beware if you're rock tumbling in the house, even with the noise-reducing barrel.