ZORUNNA 6 Pack Diamond Hand Polishing Pads, Diamond Sanding Pads with Foam Backing 60/100/200/400/600/1000 Grit, Sanding Block for Glass Wood Ceramic Marble Metal Tile Tools.

My local rock club's "juniors" (kids) spent an hour last month hand-polishing various rocks with some success. They were taught to use a succession of ever-finer grades, using these (there are various similar products to choose from): https://www.amazon.com/ZORUNNA-Diamond-Polishing-Sanding-Backing/dp/B0DGKTT918These sanding blocks were fished out of a bucket of water by the kids, so they were used wet.