🪨 Transform your stones into museum-worthy gems—don’t just polish, perfect!
The National Geographic Rock Tumbler Grit and Polish Refill Kit offers a complete 4-stage silicon carbide grit system designed to polish up to 20 lbs of rocks, gems, and glass. Compatible with all rock tumblers, it features easy-to-use, securely packaged grit containers and is developed by Blue Marble, an award-winning educational brand.
Item Weight | 1.78 Kilograms |
Item Dimensions | 5.5 x 5.5 x 4.25 inches |
Size | Medium |
Material Type | Carbide, Abrasive, Grit, Silicone |
Color | Black |
Theme | Science |
Operation Mode | Manual |
Educational Objective | Learn About Rock Tumbling |
Number of Players | 1 |
S**6
Very convenient
Everything is included except the rocks, tumbling compound an water. Good clear instruction. You may want to experiment with the length of tumbling with each grit you use based on the subject you are polishing. Good, clear instructions.
G**E
Good product
Works great
R**I
Does the job
Decent quality and price. Good selection of grits
R**K
A good product
On time and as described, it works well!
M**D
EZ directions. EZ to store.
Easy to use. Directions are clear. Tumbling my first batch of rocks. I like that the grit is in plastic jars and easy to store.
P**A
Grit
Tumbler grit is great. Each step takes the rocks to a nice finish.
S**H
Perfect for rock polishing
Arrived as expected. Previously purchased and can’t wait to use again.
K**V
The foam does what the step 4 grit should have done
First and foremost this review is for the foam pieces. I noticed the reviews are all mixed for different National Geographic rock tumbling productsI 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 coolUpdate: 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.
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