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 Post subject: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 7:04 am 
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Hello everyone.

I am new to this and i am not sure if i posted in the correct location, so if i didnt i apologize.

I am looking for a way to fast remove black mica schist from emeralds. The origin of the emeralds is Nova Era - Brazil, and it is usually craved in this schist, easily removed by hand, problem is it takes too long.

I am here to ask if anyone know about any tecnology to accelerate this process, either chemical or mechanical.

I have heard about a method using a simple device, wich is originaly used to remove stains from clothes and carperts. It produces a water beam almost invisible to the eye, at high speed, the guy that told me this said this water beam can cut a hole into your fingernail, thats how strong it is. I heard that this beam can cut though the schist easily, almost melting it, and without any harm to the emerald.

Image

Any help is welcome, thanks alot and wish everyone the best.


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 8:43 am 
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Joined: Fri Apr 17, 2009 3:53 pm
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Location: Sweden
IMO you should leave the mica in place. Always nice with a natural specimen. If you wish to remove it anyway I'm not sure if it is possible in any other way than mechanically.

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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 9:19 am 
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Thanks alot for your reply.

If anyone have any info on how to remove the mica without using mechanical methods, please advise.

Thanks alot:)


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 10:17 am 
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Location: Texas
I know that certian acids will desolve the matrix holding Colombian emeralds (calcite/marble?) without harming the emerald. There is possibly something similar that works on Brazillian matrix. I would not use the waterjet device you mentioned.


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 11:00 am 
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Location: Moncton, Canada
Hi,

I have one of those high pressure water guns. I believe they were originally fabric guns used by drycleaners to shoot jets of solvent through spots in clothing. They have been avidly adopted by the mineral collecting community, and are indeed a very useful device.

Mine is a Red Arrow brand, made in China. I'd post a photograph but I don't have it here to take a picture of it. Perhaps someone else will. There are other brand names. I got mine in Tucson; you should be able to find them there if you go. What catalogue companies may carry them I don't know; for that you'll need to do a google search, or perhaps contact a mineral dealer directly. One name that comes to mind is John Betts.

I believe such a gun would be at least as good as anything else mechanical. BTW I use mine also for shooting polish residue out pits or porosities in stones like agate. Works very well. In short, you're on the right track. Google is your friend.

Cheers
Hans Durstling
Moncton, Canada

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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 11:03 am 
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The only acid I know of which will dissolve the mica is Hydrofluoric acid and it will at the same time do damage to your emerald crystals...

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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 11:48 am 
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Hans Durstling wrote:
Nice tip by Hans


Hans, thank you very much for the tip. I will do a google search.

I posted here mostly because i am Brazilian, my english isnt even close to perfect and i didnt know where or how to start looking for this kind of device. Tried some english and portuguese queries on google with no sucess. Now i have something to start on. Thanks alot, will start looking asap and post here if i find something.

Nice to know that you use this device with sucess.

To everyone else, thanks for the tips and help and keep it cooming.

Best regards.

#########edit#########

Here is what i found so far:

@ Ebay - http://cgi.ebay.com/NIB-HIGH-PRESSURE-M ... 35af4f92d0

Some info - http://attminerals.com/equipment.htm guy is selling one for $140


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 12:25 pm 
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May I ask WHY you want to remove the mica?


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 12:41 pm 
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Barbra Voltaire wrote:
May I ask WHY you want to remove the mica?


Sure you can.

Well, i dont have any experience @ mining, but i am partner in a emerald mine in brazil. My partners wich are experienced miners asked me to do a research on methods to fastly remove the mica/schist of the emeralds, in order to be able to clean all our production faster, i guess.

I think the process in brazil goes like this
-> Miners boom in the mine, find stones
-> Miners take raw material off, select, process, and clean (manually) removing all the schist by hand
-> Miners shows emeralds to buyers in Brazilian market, the buyers only evaluate clean rocks i guess
-> Buyers buy (lol) emeralds.
-> PROFIT

Soon i will be making a topic asking for advice on how to deal this stones, in order to get more money off them. i guess selling for brazilian buyers isnt the best option, since this buyers probably sell off to another buyers in brazil, and this "another" buyers export the stones. I will be asking for advice in how to export cut stones, and deal directly with the final guys.

Thanks alot for all the advice.


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 1:06 pm 
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Yes, that's the machine, exactly. I think it's a little bit better quality than mine, and for mine I payed $100 in Tucson four years ago. So 149 $ is very reasonable.

Before you rush out to buy one, you should be aware that you will have some difficulty from the fact that your crystals will (in all probability) be small-ish, say about the size of a cigarette filter or so. With something that small, it will be hard to aim the water jet at it without (painfully) hitting the fingers that hold it. Nor is it really practical to put a handful of crystals in a tray and gun them all together. The water jet will throw them all over the place. Where the gun works really well is when the specimens are big enough to hold comfortably, once you get to about the size of a packet of paper matches, in that range. For emerald crystals that you have to hold *between* your fingers it won't be so easy. But of course I don't know your emeralds; maybe they are as big as footballs. :)

In any event, good luck!

Hans in Moncton Canada
another snowstorm on the way

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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Fri Jan 21, 2011 1:16 pm 
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Hans Durstling wrote:
Another good tip quoted :P


Hans, thanks again.

I guess they plan to hold this stone with some kind of tool like a picker, not sure. This week they took a pretty big stone from the mine wich made all the investment worth it, but from what i see it is usually small stones, so i will pass your hint along.

Thanks alot and best regards.


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Sun Jan 23, 2011 1:10 pm 
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the only way would be mechanical work, however, considering your emeralds crystal are already showing many fractures, I'm pretty sure these will explode into pieces during the process. Moreover, these crystals look much better on matrix and probably worth more money that way, in the eyes of a collector.


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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Sun Jan 23, 2011 4:22 pm 
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Good suggestion Cascaillou; it can be a way of getting some value out of crystals that are not gem grade. For the collector market specimens should be attractive; as the term has it, they should "present well," for example a grouping of smaller crystals around one central larger one. A very important consideration for the collector market is that the crystals must be entirely undamaged.They can have natural fractures (although these are never really welcome) but there must be NO man-made chips or damages. Often it is difficult to get that message through so many middlemen to the place where it is important, namely the miners themselves who are detaching the crystals. A single wrap with newspaper is not enough protection - a specimen must be cushioned, cushioned, cushioned. The number one publication in this field is the Mineralogical Record - http://www.minrec.org.

In that publication there's an absolutely excellent account by Dudley Blauwet of several mineral specimen collecting excursions to Southeast Asia - to Sri Lanka, Pakistan and Afghanistan, across borders, way up into the mountains and into the villages. This will give a good introduction to the world of the specimen dealer/collector - and it's riveting good reading. That account - in downloadable PDF format, is here - http://www.minrec.org/journal.asp - scroll down until you come to the Dudley Blauwet story.

Cheers
Hans Durstling
Moncton Canada

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 Post subject: Re: Remove black mica schist from emeralds
PostPosted: Mon Jan 24, 2011 6:14 am 
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Hans Durstling, cascaillou

Thanks for the tips, i will give that PDF a read for sure, among with other interesting things i found on this link you gave me.

Just for the record, i think i may have expressed myself badly here. Those photos i posted are not from the mine, i just picked those on google to show what i was talking about since i wasnt sure if the materials were called Schist/Mica - Sorry about that

The mine is producing gem grade emeralds. All the production that is not gem grade is saved for buyers from India that come to Brazil like twice a year. My questions about using the Water gun and chemicals were related to this gem grade emeralds. For some reason my parter wants to find out about a fast and effective way to clean the stones.

Best regards,


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