I’ve got a smoky down to the pre-polish (8000#) but it will not polish (50000#), it’s a competition stone so I can’t use an ‘Ultra-lap’, which I would if was a commercial stone, Any ideas? I’ve never had this problem with quartz before, yes it a mongrel to polish, but never had it refuse to take a polish.
Quartz usually polishes well with cerium oxide or zirconium oxide. I use zirconium on a Creamway or Darkside, but if you’re concerned about flat facets, I’d use a BATT, or better, a Matrix.
Another option for cerium oxide is a CeOx lap from LightningLap.com.
If it were me I would use a Batt lap. Combination would be Batt + 100K for your competition stone. I get excellent results with this combination on Quartz. Flat facets and a great polish. But that’s just me. I haven’t used some of the newer laps out there and the results from them may be just as good. If you don’t own a Batt, you should.
I’ve never had much luck with diamond on quartz at the polish stage. Good old cerium oxide on something like what Tom recommended, a light touch so as not to round edges too much, and a good sweep, and I think you’ll have a winner.
If it gives a some trouble with cerium oxide, add a little chrome oxide (10-20% ChrOx/CerOx).
I use a Batt with WD40 wiped almost dry with a blast of Crystallite spray 50k diamond. This is all following 3k prepolish.
San Marcos, CA
I have had the exact problem you are having none of the suggestions above have worked. It seems that smokey quartz d I especially this alot. I learned how to facet mostly on smoky quartz. For a better lack of words it seems that smoky build up a harden shell after its first polish. I have had to go back to a fine grit lap very lightly hit the facets again then using 50 aluminum oxide for the 1st polish then 100k diamond spray then 200k graves is the name brand but any kind works. This procedure gives the best polish I ever done on smoky quartz. I have often wondered if the b smoky quartz really builds up a very hard and resistance film sometimes. This has never happen on amethyst or clear quartz just smoky quartz. The quartz came from hiddenite N.C. I often wondered if the area it comes from has something to do with it.
again a tin lap with 50,000 diamond powder—no oils of any kind as it just slides your stone over polishing agent. use a (very) slow speed to polish and a drip rate about 20-40 seconds– make the diamond powder, applied by finger tip,a muddy slur. the diamond will charge into the surface a little to prolong polishing. i have students and past students using this way/method and have polished smoky over 150+ carats with very little problem. i have a quartz egg over 400 carats polished this way and right now a laser YAG over 2000 carats that will be an egg, polished that way on same lap.
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