Help Cleaning Brazilian Emeralds

I have a minor in chemistry, you can use acids safely if you have correct safety equipment and procedures. You can research for free at www.osha.gov Hydrofluoric acid is probably not a good idea for beryls or other silicon based minerals. It could ruin your stones, and for beryls or other gemstones that contain highly toxic elements such as berylium in their crystal matrix or chemicals that will react with the acids, it is dangerous.. FYI wear a respirator when grinding emeralds with cutting equipment of any type ( dremel, cab cutter, etc), wash hands and face carefully immediately after such work. HF is a pain to handle, anyway, since it etches glass and the fumes are highly dangerous, true for any concentrated acid, even hydrochloric. Oxalic acid is toxic, but should dissolve or at least soften a mica-schist matrix if kept over 160 degrees F (but well under 221 F ) for day or two, several weeks at room temperature with replenishment of acid and water as material breaks up--- some emeralds are loaded with gas and water inclusions, so don't bring them anywhere near the boiling point of water at your altitude--they may shatter. If you are uncertain, pick out a few pieces of "jardin" with obviously formed colorless or dull greenish crystals, and experiment with them. They are probably only good for the garden, anyway, as the name hints, so if they become shattered, no great loss. NEVER mix acids, this can be fatal, never pour water over concentrated acid (common sense test--if the acid produces fumes when container is opened,it is concentrated)--this can be a horrible mishap--I have seen both accidents in the lab.

Terry,
You will need to post a picture of your EBay emeralds. With a picture to work from and to ask questions about you will probably get a much more focused response to your question and a much better chance of improving the value of your specimens.

Rock Currier
Crystals not pistols.

Mine are not Brazilian, they come from the US and I wanted to do the same thing. A gemologist told me to use 50% muriatic acid as a soak. I read to use coca cola and have been doing that... down 2 bottles of coke but the emeralds are coming up nicely and there is no danger.

The gemologist also said I could tumble them with sand and that would wear away the shist. I don't have a tumbler so that isn't an option right now.

How did yours turn out?

PTF

I have some of these as well, and have been looking for a way to clean them up a bit, though I am a bit wary of using chemicals as I don't have any formal training in their use. However, I am extremely safety minded in all that I do, so I would be willing to use somewhat common chemicals if instructed well. I do a lot around my home with tools, and have never had an accident, but I believe this is because I go overboard with regard to safety. I have some rotary tools, as well as a compressor and quite a few other tools, so I may try mechanical means to clean the samples.

The samples I have are most likely Brazilian, and look to be in a mica schist matrix as mentioned by someone else. I am at work now, but I will try to post a picture later today when I am at home. I know they are really not worth much, and just want to clean some of the matrix off to get a better idea of the crystals/structure, as well as practice my trimming skills.

One other thing I have noticed with them, is the fact that they have a strong odor of oil or petroleum. I figure that this is the result of their extraction method, in that some type of tool was used as well as a lubricant. I am just curious if there is some easy way to clear the smell from them. Thanks-

Quote

One other thing I have noticed with them, is the fact that they have a strong odor of oil or petroleum. I figure that this is the result of their extraction method, in that some type of tool was used as well as a lubricant. I am just curious if there is some easy way to clear the smell from them.

Nope, oil is sometimes used as a "filler" to make the stones look better.

[www.ganoksin.com]

Hell, I love chemicals, and even have a T-shirt that says so, but I stand by my opinion that somebody buying low grade emeralds from eBay is perhaps not in the position to be using hydrofluoric acid.

Though of course I may be mistaken, and they have a nice little lab in the backyard, complete with fume hood, quality safety gear, and waste disposal procedures. Backed up by some education and hopefully that ever so rare ingredient these days, common sense.

I don't want to get into a huge discussion about relative risks, but some would say there's little to no risk in the average mine. Call me a paranoid fearmonger, but look at it this way: we live in a world where people severely burn themselves with cups of coffee, then sue for millions.

So no, let's not encourage folks to go out and play with HF to make semi-attractive green rocks slightly more attractive.

(No disrespect to Brazilian emeralds, I just bought a couple, but they certainly don't compare to Colombian, for which I would gladly perform my chainsaw-juggling act, blindfolded, on a tight-rope, over a pool of acid, while drinking extremely hot coffee.)

T

Hi, Would you share how strong an oxalic acid solution you use? I have NC emeralds I would like to clean up.

Thanks.
PT

Are you trying to clean the "iron stains" off of your emeralds? If so, consider using iron out rather than oxalic acid. You can treat your emeralds like quartz crystals in so far as chemical cleaning is concerned. See the article on cleaning Quartz.

Rock Currier
Crystals not pistols.