Items Needed for Cutting and Polishing Opal | Johno's Opals
WEBJun 7, 2010 · 7. Wet and dry sanding paper. As mentioned earlier you can cut discs from standard sized sheets of wet and dry sanding paper. You need this type of paper because the opal needs to be kept wet at all times during all of the cutting, sanding and polishing stages. I use 800 grit paper for the initial sanding and then 1200 grit for the prepolishing.