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? Jenna http://www.mindat.org/forum.php?read,19,251931,251931#msg-251931 Tue, 18 Jun 2013 21:32:22 +0000 Phorum 5.2.15a http://www.mindat.org/forum.php?read,19,251931,252021#msg-252021 http://www.mindat.org/forum.php?read,19,251931,252021#msg-252021
Jenna]]> Jenna Mast Mineral Cleaning and Preparation Sun, 12 Feb 2012 06:42:42 +0000 http://www.mindat.org/forum.php?read,19,251931,251986#msg-251986 http://www.mindat.org/forum.php?read,19,251931,251986#msg-251986
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. van Laer Mineral Cleaning and Preparation Sat, 11 Feb 2012 15:59:29 +0000 http://www.mindat.org/forum.php?read,19,251931,251967#msg-251967 http://www.mindat.org/forum.php?read,19,251931,251967#msg-251967 Some ideas:
toothpaste and brush (and time...)
acid
ammonia
polish paste/pad for metals objects
an home made electrolytic device

However I've never tried any of that.]]> Luca Baralis Mineral Cleaning and Preparation Sat, 11 Feb 2012 10:54:27 +0000 http://www.mindat.org/forum.php?read,19,251931,251940#msg-251940 http://www.mindat.org/forum.php?read,19,251931,251940#msg-251940
Try using a wet Brillo Pad. I have used them with harder gem minerals to remove thin coatings.

Best,

Joe]]> Joseph Polityka Mineral Cleaning and Preparation Sat, 11 Feb 2012 02:36:33 +0000 http://www.mindat.org/forum.php?read,19,251931,251931#msg-251931 http://www.mindat.org/forum.php?read,19,251931,251931#msg-251931
Jenna]]> Jenna Mast Mineral Cleaning and Preparation Sat, 11 Feb 2012 01:44:24 +0000