We have 24 pounds of apaches tears that I collected in Nevada. We have been working at polishing them, but having lots of problems. The early tumbling stages went fine. My wife used a combo pack of polishing media that she bought on eBay. This is what we believe we used:
Course grit (70 Grit Aluminum Oxide)
Fine grit (220 Grit Aluminum Oxide)
Pre polish (500/600 Grit Silicon Carbide)
Polish (diatomaceous earth)
The polish was unlabelled, but we found out after the fact that the polish was diatomaceous earth.
Everything seemed to go fine up to the polish stage. The apache tears/obsidian came out looking worse than they went in. The diatomaceous earth worked awful on the apache tears/obsidan.
My wife put them back in for the pre-polish stage, and they came out looking better. So we tried to polish them again. This time we used cerium oxide. Again, the apache tears/obsidian came out looking worse than they went in. Not nearly as bad as what the diatomaceous earth did though.
Here is a picture of what the rocks looked like before (left) and after (right) the cerium oxide polish stage.
So we are going to try again. We have read that we probably want to use some sort of filler to buffer the rocks and slow down the polishing. This time we are polishing them with cerium oxide & plastic beads.
Hey there…
I collected a 5 gallon bucketfull of apache tears near Tonopah, NV some time ago and am now getting into the lapidary phase. I just acquired a tumbler and since I am going on a trip to the Hauser Geode Beds this month (April, 2010) it may be late in the month or even May before tumbling takes place, but I will let you know here what my experience is.
Many of my Apache tears ARE polished by wind and sand on the top surface (shiny) while they have a matte finish on the surface that was below the surface of the ground.
I find THAT a very interesting look for a “specimen” item. I sell these at a flea market along with geodes.
Comment by Movieman990 — April 2, 2010 @ 12:06 pm
Ron, I look forward to hearing about your experiences polishing the apache tears. We are still working on it. We have them polishing in red rouge now. We’ll see how that works.
Comment by Rob — April 2, 2010 @ 1:15 pm
You need to thoroughly wash your barrels in between grits what may be happening is that you are contaminating the grit with residue. When polishing it’s often a good idea to have a completely separate barrels for the two final grits, and use the filler pellets in the final two, but use new ones for each grit.If there is one tiny piece of any of the previous grits you won’t get the next polish level.
Comment by steve — September 16, 2010 @ 1:17 pm
If you don’t have extra barrels, scrub them in between with a heavy scrub brush as well as a toothbrush for the corners, as well as the gasket or lid. look at it in the light , if you see any metallic or silvery shimmer, there is still previous grit in the rubber.
Comment by steve — September 16, 2010 @ 1:23 pm
lastly do a 120 220 400 500/600 tin oxide, rouge.
Comment by steve — September 16, 2010 @ 1:26 pm
Thanks Steve, that wasn’t the issue. We always thoroughly clean the barrels before the next stage by running the rocks through a middle stage in water and laundry soap. We finally figured it out. First, we found that red rouge worked much better than the cerium oxide. Also adding sugar to slow the polishing progress. We finally got them polished like glass! I need to write up the process.
Comment by Rob — September 16, 2010 @ 1:39 pm