I have an amethyst crystal cluster, and I need help cleaning it...?

Question

It is absolutely beautiful, with the entire cluster being about 4.5" wide and 3.5" long. The only problem is, there is a thin, crusty, white film (some type of mineral deposit?) all over the crystals that is VERY hard to remove. It reminds me of tartar on a person's tooth that a dentist must scrape off with a tool (bad analogy, I know). It seems to become opaque when it's wet, but will go back to being white once it dries. I can't scratch it off with my fingernail and I don't want to use something harder as it may scratch the crystals. What can I do to remove this stuff? Sorry, I don't have a picture. My camera isn't working.

Answer 1

I used to work at a jewelry store and we used to suggest soaking jewelry in a half/half mixture of water and ammonia. It works well warm (but don't microwave your jewelry!) and helps if you gently shake the mixture with your jewelry in it. You can use a soft toothbrush, but I wouldn't suggest it if the piece is very old as any prongs holding the stones might break. Don't use toothpaste or any abrasive cleaners.

Answer 2

It depends on what the crust is.

Amethysts is a quartz species (silicone) and is immune to most acids.

You could try a bit of strong vinegar or dilute hydrochloric acid on a small inconspicuous spot.

If the crusts is a form of calcium it will be eaten by the acid.

Answer 3

The crust might be carbonate/sulphate encrustations, try scrubbing with soft tooth brush using  dilute hydrochloric acid or dilute sulphuric acid. Remember to use acid proof gloves and  rinse the specimen and your hands with running water.

It should work, try to also check it is not a paint/polish coating, in that case you have to use some paint dilute or acetone etc.

thnks

Answer 4

The white sounds like calcite.  Try vinegar.

If you used a dental scraper and couldn't get it off, then the mineral's not calcite.  In fact, the mineral may *too* hard to get off, since its hardness seems to be the same as the amethyst.  It might even be a feldspar - which you *won't* be able to get off.

If a steel wool pad won't scrape it off, then I don't think you'll be able to get it off.  You may at that point probably want to take it to a local gem show, club, or geology department and try and have someone identify the substance so you can see if it can be removed or not.

Answer 5

Amethyst is a specific form of quartz, which is extremely stable and fairly hard.  You can try any store bought product on it without doing it any damage.  I suggest you try using acids first.  Soak for a while then heat the amethyst in the acid- be careful not to splatter.  If none of the acids you try work then start trying with strong bases.  Drano and other drain cleaning products should work.  ALso scale removing liquids sold for cleaning bathroom tile may work.

You can also scrub away with all your might with a copper wire brush or steel wire brush, they can not scratch the quartz.

Answer 6

That is what the stone looked like before it was cut and polished. You would have to do the same with the rest of the stone to get it off. What you have is an amethyst geode. You would need lapidary supplies to take it off.