What to do with rough sapphires?

June 10, 2007 9:55 PM

I'm no lapidary but I need to separate some sapphires from the surrounding rock and polish them (slightly, I want them to stay rough, no shaping/mounting.) How can I do this without spending multiple paychecks on professional lapidary stuffs?

After unexpectedly befriending the owner of the Old Pressley Sapphire Mine in NC, I got some (delicious) personal time with a chisel, hammer, and bountiful cliff side. As a result I've got several pounds of specimen sapphires still in their gleaming white surroundings...and, in a month, will probably have twice as much. They're not quite ring quality but they're beautiful grays, the sort that become cabochons. Because they're useless locked in the rock, I need to extract them. I also want to polish them slightly so they're more appreciable.

The problem is, I can't afford professional lapidary equipment. As a corollary, though, I don't need professional results--so what can I do? I've done some preliminary research online but I can't find any good resources with the obvious keywords. And I know firsthand that commonly available diamond Dremel tips grind down/disintegrate(!) when faced with rock, but maybe I need special tips? Rockhounds, unite!

posted by Phyltre to sports, hobbies, & recreation (6 comments total)

What are the sapphires embedded in? I used to do lapidary and rock hounding when I was a kid (and think I'm going to start the lapidary side again at some point). I've got a couple of 2" diameter sapphires and I never actually cleared them but I did some tests with a couple smaller ones using a diamond saw. You could rent a diamond saw for cutting tile, it'll be a coarser cut but a whole lot cheaper than investing one of your own.
posted by substrate at 10:10 PM on June 10, 2007

Well, the substrate is mica (no problems there) and--err--feldspar, I believe it was. White stuff you make china from. Here's an image of most of the haul, only partially washed:

http://img171.imageshack.us/img171/57/hpim0266gw9.jpg

Any ideas on the cost and logistics of getting a diamond saw?
posted by Phyltre at 10:26 PM on June 10, 2007

Tumble with sharp crushed quartz, mohs 7. this will easily cut the felspar/mica mohs 5 and not harm your gemmy bits, mohs8/9. I use this technique to release jade lenses mohs 6 from serpentine mohs 3/4/.tempered glass instead of quartz
posted by hortense at 12:09 AM on June 11, 2007

American Science and Surplus and Harbor Freight have diamond files rotary tools, diamond discs, cheap.
posted by hortense at 12:22 AM on June 11, 2007

hortense' idea sounds really good if the pieces aren't too huge (or if you have a large tumbler). A new, yet poor quality saw for cutting tile can be as little as 100 bucks so renting a decent one should be fairly cheap.
posted by substrate at 8:26 AM on June 11, 2007

Have you checked to see whether there is a lapidary/rockhound club in your area? There's one here in SF that has a nicely-equipped clubhouse in which members can use the equipment to do all sorts of lapidary work. If you can find a club, a year's membership will probably be a lot cheaper than buying your own equipment. Plus, the more experienced members could show you how to do various techniques.
posted by Quietgal at 11:57 AM on June 11, 2007