I don’t use the diamond paste that comes in the syringes in particular but we use a polishing compound called white diamond as one of the last steps when we make jewelry. It’s pretty much the same in that it has crushed diamonds in it as the abrasive. Final step in polishing gold or silver is red rouge which uses ferric acid as the abrasive which is close to 100,000 grit. (I know we’re mostly talking about polishing plastic in this thread. Sorry)