Polishing Corundum (Sapphire and Ruby)
Please note that the pictures of all the sapphire/ruby stones have NOT been polished
yet. They will be this winter using the methods described below.
Polishing sapphire was giving me trouble. When I realized it's a precious stone
and it needed to be treated as such, I made gains. Clean the stones after each
grit treatment really well. Each stone must be polished separately. If you tumble
large Bancroft golden sapphires with little lily black stars you get very very
tiny black sapphires. It is best to tumble larger golden sapphires with feldspar
and/or quartz. Tumble course, medium and fine. Stop. Pull out the smoothest.
The rest go back into your next load of fine grit. Get to know each stone.
You're going to be spending a bit of time together. Old school, the old timers,
say to use cerium oxide on leather. I have been working on new ways of polishing
corundum/sapphire and have been getting good results. I'll be doing the red and purple stones that you
see listed on the web site, this way. I'm new at this and others must have their
own methods. If you are using maple and getting good results try some of our north
shore tamerack. Remember sapphire is the second hardest stone. I gave a large
stone to local Pebble Pups saying if you can scratch it I'll give you $10. Maybe someday
a kid will get a sawbuck and a stone for Mom and Bancroft will be known for diamonds
also.
Sapphire will eat the lids of the tumblers and spit out bearings if you try to
rush the process. Slow sanding is the best. As always, if I've made an error
feel free to flame me with a correction email.
If you know of a better way that works for you I'd be happy to hear from you.
Sapphire
Ruby
Polishing Corundum
