I picked up this stone in an antique store today. I know somebody will be able to tell me which one it is or the type. At the Missouri Meet I saw one very close to this one and the slurry sure looks the same. I took the pics with my phone so they aren't the best but the slurry is a purple/brown in color. I put some water on the stone and used some 600grit wet dry sandpaper and the slurry popped up fast and there was a lot of it. On the back you can see parts of a label.