8000 Grit Aluminum Oxide Rock Tumbler Polish – Final Stage (Step 5), High Gloss Polishing Powder for Rocks, Gems, Glass & Jewelry Making, Polish Refill, 1 lb

Amazon has an 8000 grit, but it’s also $25/lb. Kingsley North’s prices for 22,000 is pretty cheap, but shipping isn’t. Here’s what I get from Amazon https://a.co/d/0dRQXRB6