National Geographic GemFoam Reusable Rock Polisher for Rock Tumblers | Reusable Polishing Foam, Adds Shine After Grit Cycles, Rock Tumbling Media, Works with Tumbled Rocks and Minerals

First and foremost this review is for the foam pieces. I noticed the reviews are all mixed for different National Geographic rock tumbling products I am very pleased with the foam to use after step 4 which as others have stated left the rocks or minerals still very dull not shiny, this got the job done. Just use it after step four if you were using National Geographic grit as instructions suggest. I am also getting a better step 4 from another brand to compare that with the foam to see if it does better or the same as foam but as for now I am very pleased. Here in this photo I tumbled a chert in the foam after Nat geo 4 step. Chert is the stuff you commonly see in Some concrete It has a hardness of seven I'm thinking that at least for the foam anyway the harder the rock the better they shine like this one does quite well. I am currently tumbling a less hard rock serpentinite with hardness of four or five and it’s not getting quite as shiny but I think it’s still better than before, I am letting it tumble longer. So Basically if it’s a six or seven or harder it will shine better using these whereas step four did nothing using National Geographic. It’s cool that these rocks in the photo came from my backyard doesn’t look like something from a backyard once you shine them up like this pretty cool Update: The pictured rocks turned out amazing, however the serpentinite never got shiny. My conclusion is that these foam pieces only work for harder rocks that are somewhat smooth to begin with. The rocks in this photo were somewhat smooth to begin with but not shiny the foam without a doubt made a huge difference the light did not bounce off them like it does now also they are now silky smooth as opposed to somewhat smooth. So if you use these bear in mind they will only work for harder somewhat smoother rocks. I did use a better step 4 for my serpentine and I still see no difference so just like with the foam I think some rocks are just not going to shine as well as others. The foam still gets a five star for what it did to that chert though and you do need to go the full 3 days of tumbling because after day one I saw no results. A total of five days in the foam wouldn't hurt either I was pleased with 3 though.

If you enjoy polishing rocks with a tumbler, the gem foam are a nice little trick to use to get that final polish. I have been working with rocks that are not always ideal for polishing. I use the gem foam after I burnish my stones and the gem foam helps to get that extra bit of shine out of my rocks. I cannot speak as to how many batches one can get out of the gem foam before they no longer do their job, but for the price they are worth the purchase.

We bought these looking for another way to try to get our rocks to shine with a wet look. They make our rocks a little more smooth, but we still can’t figure out how to get the wet look on them. They are reusable, but you need to make sure you keep track of what you used them with or after because you don’t want to add grit to them. I would say they worked okay. The price was decent.

To clean and smooth rocks, then polish them so I can have jewelry I had wanted in the first place - is so awesome. Years ago I had a small rock polisher and it was noisy and didn't do very good job. This polisher is so much quieter, we can have it in the house and not a far away shed. The rubber of drum, wheels, top are all awesome. Keeps it quiet and with the pellets and sponges, we find most rocks take less time than suggested. We got it in August 2024, and it has ran every day but maybe 2 days sense. Love it

Great tumbler. Use it frequently with no problems.

I think the product was fine, but I didn’t notice any real difference in terms of polish quality/shine. In all fairness, I haven’t been unhappy with the polish from my Polly Plastics grit but wanted to see if it would make a difference in my burnishing step - it didn’t. Also, expensive for what it is and how much you get.

I have only done one round in my tumbler, and one for a few days. But there was some shiny rocks already. They work great, I wish there were a few more cubes so I could do bigger patches but, theyre awesome

In my experience, this media help give a great final polish during stage 4 tumbling. I made the mistake of trying to use it for both stage 3 and then stage 4, after using for stage 3 the media was impregnated with the pre-polish grit, I bought a second bag of this media and have been using it for the stage 4 polish cycle and have phenomenal results.

facile a utiliser apres avoir utiliser mon 1200 grit

Easy to use, but doesn’t perform anywhere near the advertising

Producct did not polishrock in tumbleer

Don't get me wrong, I love what they do. It has helped a bunch of my river rocks fet that extra oomph. However, when the Nat Geo rock grit kit with all 4 grits, and ceramic and the 1 Oz of this foam tumble media is only like $5 more, this feels like a money grab rip off. There should be way more foam pellets if getting this singularly.