Dear Noel: Been there, done that. To repolish any soft bead, i.e.,
Malachite, turquoise, I usually restring them on a very strong
fishing line and head for my buffer and zam. By taking my time and
keeping control of the beads I am able to bring back or make better
the polish and luster of these soft beads. Working patiently prevents
heat build up and the melting of the fishing line and consequently
the flying of beads. I once made a batch of large malachite beads
into chips when I tried to tumble polish them with a vibrating
tumbler. I found out that the better way, albeit a slower way, was
back into a bead mill for fixing chips and other stuff on salvageable
beads. Sincerely, Marty Galarneau Galarneau’s Gems
http://www.galarneausgems.com