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Issue with polishing quartz
I have a piece of natural quartz that I am cutting now. After I got it roughed in when I started working on the pavilion, there were a lot of inclusions and they were breaking off and causing lots of scratches. The piece was tall so I cut it down to get past the visible inclusions. Now I’m working on the pavilion facets and when I get to the polish, it seems to polish fine but when I look at the facet at an angle the surface is uneven, kind of like an orange peel. You can’t see this looking straight onto the facet. Has anyone every seen this in quartz before?
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4 Replies
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Yes, Quartz has this problem. Sometimes it is so severe that the surface looks like a Herringbone pattern. The Quartz is variable hardness in spots. The softest spots will over cut and look uneven. The classic solution is to cut with 600 grit, preform with 3k diamond and polish with Cerium. However, nothing is for certain. You may need to experiment. This type of material does need a higher grit preform. No going from 600 or 600/1200 to polish.
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Isn’t it any kind of twinning? http://www.quartzpage.de/crs_twins.html Sometimes helps change position on lap or switch rotation of lap. I heard it’s not happen when using diamond to polish. But i never try to use diamond for polishing quartz, alway DarkSide with cerox.
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Yes, it is due to twinning and the resulting subtle differential hardness with lattice orientation. The way to avoid it is to have a very fine pre-polish so that the final polishing step is quick.
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it does so also with the growth planes too. they grow in platelets. topaz has one plane, sapphire 3 planes so has quartz. then add flaws, stresses, and micro rods of rutile, bingo prob’s. we just use a TIN lap at very slow speed and 50k diamond powder and just enough water to keep a muddy slur. then hope for best. i ended up making my own TIN lap to get the best i can polish. and have a few out there with very happy campers polishing.
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