As I did not have an air compressor, I decided to use a steel brush attachment that came with my dremel to remove lepidolite coatings from tourmaline that I couldn't removing any other way. This works, however it also leave a thin metal deposit on the crystals. I only did a test section. I don't want to continue until I know how to remove the deposit. Does anyone have any suggestions?
Complete removal is somewhat dependant on what type of metal brush you used: steel wire would require a soaking in warm/hot hydrochloric acid (muriatic acid), while a brass brush would require a soak in waek nitric acid. Both reactions would be facilitated by adding heat, but either will give off noxious fumes, so please use caution and do this under a fume hood. Chris
William C. (CHRIS) van Laer: "I'm using the chicken to measure it..."