Re: Polishing amethyst crystals
There are two possible problems that I can think of. One is that there is a thin mineral deposit on the crystals. The other is that they are slightly etched.
If it is a mineral deposit, it may be a carbonate. In which case, acid should remove it. My first attempt would be to soak the specimen in white vinegar over night and then rinse it with plenty of water. Actually, muriatic acid (hardware store) will do the job quicker and better, but unless you are used to handling acids, it is better to use the vinegar.
If there is etching, there is not much you can do.
From Don Peck - July 14, 2007 at 10:26:27