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Synthetic Malachite?

Posted by Russ Nobbs  
Synthetic Malachite?
September 24, 2008 12:43PM
Has any one had experience with "Synthetic Malachite?"

We received samples of well oriented beads that the Chinese vendor admitted were synthetic malachite coming out of Hubei China. The banding is very similar to real malachite, the beads have the heft of malachite but the price is too cheap for this quality of banded malachite.

I'm very familiar with totally imitation "block" plastic made by swirling or layering several colors of dyes into plastic that is made in the US and in China. These beads do not look or feel like the plastic block. The banding is not straight lines as in one form of plastic block. Nor does it look like the compressed nugget type of material that is so common as "azurite/malachite" made from crushed lapis and malachite held together with resin and dye. I have pictures of those products posted on my Flicker pages http://flickr.com/photos/51181878@N00/

I don't have proper equipment for testing stones but tried some basic field tests. The bead does not feel like plastic when tapped on the tooth. When hit with a hammer, a bead breaks into 3 sections. The sections do not have the conchoidal look of glass. The bead did not break along banding lines.

I'll try to get a good close up photo of broken beads to post with whole beads but I thought I'd ask about it in case someone is already familiar with the material or can suggest some other basic tests I can use.

Thanks for any suggestions!

Russ Nobbs (www.rings-things.com)



Edited 1 time(s). Last edit at 09/24/2008 12:44PM by Russ Nobbs.
avatar Re: Synthetic Malachite?
September 29, 2008 08:18AM
    
Russ,

Malachite will fizz in dilute muriatic acid - say 5% HCl(aq). Crush a little, add a drop of acid and then a few drops of ammonium hydroxide - it should turn blue. If positive on both, you will just know that you have something containing carbonate and copper.
No experience with synthetic Malachite as such - only the plastic beads you mention. Could it be a by-product from a chemical plant?

Claus

____________________________________________________________________________
Claus Hedegaard
Google me to find me!
avatar Re: Synthetic Malachite?
October 03, 2008 01:22AM
Rus,
Hubei, specifically Diya is the home of 2000 plus year old bronze culture and I visited several lapidary factories there that were working with chips and pieces of malachite/azurite "rock" that was being used to make chip necklaces and other items. It would not surprise me considering the low quality of their feed stock if they were somehow using some of the local low grade malachite and making some sort of plastisized material out of it. Sorry I can't be of more help.

Rock Currier
Crystals not pistols.
Re: Synthetic Malachite?
October 10, 2008 03:02AM
Thanks for the simple tests to try. I've got nitric and H2O2 but not hydrochloric on hand. I'll post back with results.
In the mean time here are a couple of pictures under flash and available fluorescent light of 14mm beads of this material. I'll post a close up of a split open bead shortly.





Here is a shot of typical blocks of plastic material imitating Malachite followed by a close up of a sample card of malachite. Both are from a recent trip to China.



The new material sold to me as synthetic malachite is much better looking than the plastic material. I'll post what I Iearn after testing a crushed bead.



Edited 1 time(s). Last edit at 10/10/2008 05:31AM by Russ Nobbs.
Re: Synthetic Malachite?
October 10, 2008 05:29AM
    
Hi,

If it is plastic or contain any kind of polimer, you should be able to burn it. Try to put a fragment on a "clean" flame, you could see smoke and it should smell like burned plastic. the remained solid part should be composed by the inorganic power. On the other hand, you can put fragments into some organic solvents, like acetone, or paint solvent, or dimethyl cloride, or whatever you can use. It is difficult to suggest the correct solvent, it depends by the plastic. (some plastics are inert but I don't expect this kind of precius materials). In this case you should see some "degradation" of the material.

Dario

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Dario Cericola
My Mindat page --> [www.mindat.org]
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avatar Re: Synthetic Malachite?
October 10, 2008 02:57PM
    
I certainly hope they aren't selling the pink material as "red malachite" ;)
Re: Synthetic Malachite?
October 10, 2008 03:45PM
    
They may not market it as "pink malachite" but you could probably make a safe bet that the finest banded "rhodochrosite" is about to hit the market! The Argentinian military, which controls the source of the "Inca Rose," cut off the Chinese from buying their scrap grade material because the Chinese were buying it cheap and dying it. Perhaps they are ow "manufacturing" it.
Re: Synthetic Malachite?
October 10, 2008 05:10PM
Hi,

We have synthetic malachite in our (GIA) collection that I still find hard to believe are synthetic. They look like typical botryoidal malachite from the Dem. Rep. of Congo! I have yet to find out more about their origin and nature, but I shall endeavor to do so because of this thread.

Cheers,
Mark

Assistant Curator
GIA Museum
Re: Synthetic Malachite?
October 10, 2008 11:15PM
<LOL> No, David, it's more likely to be sold as "laser enhanced rhodo something or other." I just didn't crop the right part out of the card. Here's the whole sample card.


Mark: Are the samples in the GIA collection beads, cabs, slabs or what shape? I'm also impressed by the look of these. As usual we had to ask a lot of questions of our vendor to get him to add he word "synthetic."
Re: Synthetic Malachite?
October 11, 2008 04:12AM
Here is the inside of one bead cracked open with a hammer. It broke into 3 large pieces. Very little was lost as the bead can be reassembled into a round bead.


NH
Re: Synthetic Malachite?
October 11, 2008 06:31AM
Fracture looks more like plastic than malachite - seems a little bit translucent as well. I would say that they are synthetic. As others have mentioned, do they burn or melt in a flame?
Re: Synthetic Malachite?
November 21, 2008 03:57AM
I found time to test the beads a few weeks ago. (Sorry I took so long to post the results!)

It IS a resin based imitation material. It failed the acid and hydrogen peroxide tests. No reactions at all.

It softened up in the flame. It didn't exactly puddle and run but it smoked and burned as long as I kept it in the torch flame.

We've changed our description and no longer call it "synthetic." Instead we are describing it as man made malachite which is an imitation material.

One of the reasons we decided to carry a cheaper man made stone in our beads is that we can rarely find real malachite of any quality. Do any of you know it the scarcity of good malachite is due to political problems in the Democratic Republic of Congo (formerly Zaire) or if it’s just that the stone is running out?
Re: Synthetic Malachite?
November 21, 2008 04:45PM
    
"Instead we are describing it as man made malachite ..."
That's not correct then. It's a (resin-based) malachite imitation (if you are reluctant to call it fake).
Re: Synthetic Malachite?
November 24, 2008 05:37AM
<lol> "fake" when used by a seller is usually spelled "faux."

I'd rather just call it "man made imitation malachite" or just "imitation malachite."
Re: Synthetic Malachite?
December 03, 2008 10:05PM
Russ, you mentioned you have nitric acid but not hydrochloric - Nitric acid will work equally well.
avatar Re: Synthetic Malachite?
December 03, 2008 10:58PM
    
Russ,
if the synthetic material is a resin it may also dissolve in acetone (nail polish remover) which could be a quick test.
avatar Re: Synthetic Malachite?
December 08, 2008 12:17PM
.....Do any of you know it the scarcity of good malachite is due to political problems in the Democratic Republic of Congo (formerly Zaire) or if it’s just that the stone is running out?.....

Most people that have been to the copper mines around Likasi and Kolwezi in the DRC know that there is plenty of malachite left to dig. During the last ten years or so the mining activity in Katanga has become moribund because of the political instability and corruption in the country. Before the collapse of commodity prices there was a fair amount of interest in trying to mine old and new copper deposits in the region. If copper prices had remained high various companies would probably started operating some of the deposits there in a big way but with the recent financial melt down I don't think anyone wants to lend money to sink into mines in such an unstable place. During the last few years, all or most of the malachite that has reached the market, and there have been hundreds of tons of it, has been dug by local villagers going into the old abandoned open pit mines and digging down on certain benches till they hit the layer that is rich in malachite. The problem is that they have ratholed these places to death, and it keeps getting harder and harder to find good cutting grade malachite. If full scale mining is resumed in some of these deposits, tons of malachite would be found. It is one of the main ores at these mines. When this will happen will be anyones guess. In lock step with the increased difficulty in mining lapidary grade malachite, the political instability and corruption has increased, and the cost of exporting such malachite from the DRC has gotten more difficult and more expensive.

Rock Currier
Crystals not pistols.
Re: Synthetic Malachite?
February 23, 2009 07:25AM
Knute: The imitation malachite did not dissolve in acetone.

Thanks, RC, for the comments on DRC and malachite. I did notice at Tucson this year that a few dealers had large irregular chunks of semi polished malachite for sale. One at TEP in particular had some nice material selling more as curios than as cutting rough. (Maybe this is still because the DRC wants malachite to be exported as "finished goods?" That was the excuse given for the giant "ash trays" a few years back.)

In any event, one of my Chinese cutters who specializes in natural amethyst did manage to find and cut some malachite beads for Tucson this year.
Re: Synthetic Malachite?
March 05, 2009 05:56PM
I remember having bought some specimen of synthetic malachite made in Russia a few years ago.
They had the typical botryoidal shape and a little bit darker green color.
There had been a wire in the middle so some sort of electrochemical process might be possible.
As the Russians are one of the industry leaders in synthetics its likely that they tried something as their own deposits (think about the huge malachite columns or vases in the Erimitage St. Petersburg) may have been vanished already.
I also have lab grown calcite from Russia in my collection made to replace natural optical calcite in optical instruments.
So I know they tried almost everything and its likely that there exists "true synthetic" malachite and not just plastic imitations
or "reconstructed" material.

Udo J.A. Behner alias "mr.bismuth"
www.spectrum-of-stones.com
avatar Re: Synthetic Malachite?
March 06, 2009 09:51AM
Udo,
The malachite columns and vases that were the products of the great Russian malachite deposit in the Urals and the lapidary shops during the time of the Czars are, I am sure still in St Petersburg and Moscow and other places. All these items were forms covered with a covering of thin slabs of malachite and not made from big pieces of massive malachite. The slabs are carefully fitted together to preserve as much continuous banding as possible. When I was in the Winter Palace we had a Russian lady English teacher who was picking up extra income by offering to take tourists around and explain the things in the Hermitage. She was quite good, but didn't know much about malachite and was under the impression that the malachite items were made from solid malachite. At that point I became the guide and instructor and told her about Russian malachite. At the end of the tour she tried to sell us some malachite beads that were from Zaire. I told her they were from Zaire and pointed out how terrible the workmanship was because they were not very round or very well polished. She didn't believe they were Zaire because to her the bad manufacturing was proof to her that they were made with the usual low standards that many of the factories in Russia have. I had to then tell her about the Fabergé, and how that the lapidaries of Russia had high standards that continued right through Communist times. I am still not sure that she believed me.

Rock Currier
Crystals not pistols.
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