# native silver acanthite rock



## shpfrm14 (Oct 30, 2011)

Does anyone know how to etch silver bearing rocks? I would like to see the silver better.


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## Harold_V (Oct 31, 2011)

shpfrm14 said:


> Does anyone know how to etch silver bearing rocks? I would like to see the silver better.


Possibly hydrofluoric acid----but I advise you to read about the hazards before you even think of getting involved. As little as 25 square inches of skin exposed to HFL _can be lethal_. The fumes destroy lung tissue as well. It may also be impossible for you to obtain. 

Harold


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## g_axelsson (Jul 17, 2013)

That depends on what type of rock. Silver could be found in both silicate host rock and calcite rocks.

A classical location in Kongsberg in Norway, here most of the silver is located in calcite veins and can easily be dissolved out of the rock with hydrochloric acid.

For silicate rocks you need hydrofluoric in most cases. Avoid that, it's not worth the risk. Read what Harold wrote.

Göran


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## chlaurite (Jul 17, 2013)

Harold_V said:


> As little as 25 square inches of skin exposed to HFL _can be lethal_. The fumes destroy lung tissue as well.


You left out that its perverse affinity for calcium makes it directly leech bone and stimulate (pain-carrying) nerves - Making it, even without the least sign of an actual superficial burn, one of the *single most painful experiences a human can have*. :twisted: 

Honestly, Harold, it truly surprises me you would even _mention_ that as a possibility! I'd use boiling lye, organic mercury salts, cyanide, even boiling concentrated H2SO4 before I'd go anywhere _near_ HF.

It comes in at #2 on my list of things to never, ever play with - Right after FOOF :shock:


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## nickvc (Jul 18, 2013)

I can honestly say I have used and worked with most acids and cyanide but I'd have to say hydrofluoric comes out as one of the nastiest closely followed by concentrated sulphuric and caustic soda.
Although many fear acids bases can be a lot more hazardous to the user, caustic can and will do severe damage to human tissue so all please wear goggles when handling or using, gloves are a must and a decent chemical resistant apron would be handy.
After reading about foof I think that's not likely to come my way and for that I'm grateful but hydrofluoric has its uses but not to most of the members who should avoid it like the plague, it really is not necessary for our processes thankfully.


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## mls26cwru (Jul 18, 2013)

once upon a time I worked for an air emission testing company and we happened to be doing a test at a company that used HF in its process... I had a 1-on-1 plant safety training course with him so we got to talk rather candidly... at one point he pointed out the HF processing building (that was a good distance away from the main plant) and the following quote is what he told me about said building:

"you see that building over there... that is the hydrofluoric acid building... while you are here, if you happen to see a white cloud coming from that building... run like hell and DO NOT let the barbed wire fence stop you"

I think that sums up HF acid quite well.


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## cryptic (Jul 18, 2013)

Muriatic acid will etch calcite from the silver. It can be found in hardware stores. Mix half acid and half water. When done baking soda will neutralize the acid for proper disposal. Don't forget safety precautions.


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## torscot (Jul 19, 2013)

If your silver Is in calcite, the HCI method will work the best. But, this leaves your silver "burnt" for lack of a better word. gray and dull, and real crappy looking. If your material if from northern Ontario, such as cobalt or Gowganda, your silver is most likely coated with safflorite, (CO AS ) and it's brutal to get it to look good. Here's the trick to get it to look good. once you have etched it out with the HCI rinse it well with baking soda as someone said in another post. Now wrap your specimen tightly in tinfoil, make sure it is touching every piece of exposed silver, place in a bowl of regular household ammonia cleaner, leave overnight. In the morning you will find your aluminum foil is black or in some spots dissolved. unwrap your specimen, It's now coated with silver sulfide,(acanthite) but, it's loose, it can now be washed off with a toothbrush and baking soda. leaving you bright silver. If it doesn't want to come off that way, use a fine wire brush.

Here's another method, but it's a lot more severe, and has a learning curve. Use the HCI to etch out the silver. wash and clean. place in a dilute 75water 25 Nitric acid, and heat. ONLY for approx. 3-5 minutes. this will remove a lot of the safflorite, and expose the silver but it will also etch the silver. witch is fine, if your only doing it for the few minutes. wash and clean, DO NOT scrub your specimen with a brush. Again wrap it tightly in tinfoil, place in an aluminum pot filled with a saturated solution of water and baking soda. and bring to a boil on the stove for 5-10 minutes. unwrap. Your specimen now looks like crap. If you have an ultrasonic cleaner put it in there, and run, the crap falls off and you have a beautiful white silver specimen. No ultrasonic cleaner, use compressed air and water, or high pressure water. No scrubbing. This lets all the fine pieces of silver remain on your specimen and you have not just "polished" up the high points and all the edges are nice and crisp and sharp.

I have collected metallic mineral specimens from Ontario Canada for years and have leaned these methods over time and they work. Remember when you clean your specimen, always think of the final looks, can you leave a "base" of rock under it to use as a stand. aesthetics in minerals is everything. 

Hydrofluoric acid. I have used it,but it's dangerous #*%&. But it works.

If worse comes to worse you can crush it and refine it. That's what I came to this site ot learn, so I could recover my Ooop's from cleaning

Rob.


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## Harold_V (Jul 20, 2013)

chlaurite said:


> Honestly, Harold, it truly surprises me you would even _mention_ that as a possibility! I'd use boiling lye, organic mercury salts, cyanide, even boiling concentrated H2SO4 before I'd go anywhere _near_ HF.


Trust me. That was a tough call on my part. You likely understand that I do not endorse the use of HF acid. 
The problem with pretending it doesn't exist is some poor soul will discover it and not understand the ramifications of its use. Armed with that thought, I opted to make mention, although with the hazards disclosed. 

Bottom line on things like this is---some folks won't be deterred. They're going to do what they're going to do, and all the safety precautions or lack of disclosure won't slow them down. This way, at least he can't say he wasn't forewarned.

Harold


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## solar_plasma (Jul 20, 2013)

In the EU soon RF1234yf will be used instead of the old tetrafluorethan (R134a) as a coolingfluid in the aircondition system of every car. RF1234yf is known to be inflammable and decomposes under heat to hydrogen fluoride. Only Daimler and Greenpeace are trying to stop that, as far as I read. I could not find english sources, so only for the record a german link: http://www.heise.de/tp/blogs/2/154658

So this terrifying stuff will soon be potentially all around us. Just for the record, the first responding firemen in an accident have no airtight chemical suits. Could be hard to get anyone from an accident to the hospital within the "golden hour", if they first have to wait for the hazmat teams. Another question is, would it do any difference, if the patient, who has inhaled HF, would come to the hospital sooner .

To come back to the subject, I think it is important to have the facts on the table. To many individuals those chemicals are available. Only an open dialog can constitute the base for the decision, why not to use one or another material.


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## niteliteone (Jul 20, 2013)

Here is an English language Pdf from Dupont talking about RF1234yf;
http://www2.dupont.com/Refrigerants/en_US/assets/downloads/SmartAutoAC/HFO-1234yf_IIR_Leck.pdf

Here is a link to a forum where they are discussing the new HFO-1234yf refrigerant;
http://www.autoacforum.com/messageview.cfm?catid=2&threadid=20820


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## butcher (Jul 20, 2013)

Acanthite silver ore (Ag2S), being a sulfide ore of silver, I think I would investigate froth floatation to concentrate the ore, and look into smelting with iron in the flux, being aware that arsenic could be involved depending on the ore.

Call me a bit of a skeptic, but as a person who has worked in the refrigeration trade for years I find it very funny how whenever Dupont’s patent for R12 was about to expire it became so much more dangerous to our environment than the other refrigerants of similar chemical make up, not to say that release of these gases into the air of any of the refrigerants would be safe for us or the environment.

I can tell you these gases are toxic and corrosive when heated, I remember soldering in a reversing valve on a heat pump one time, left my pouch full of tools nearby, the next day all my tools were just a pile of rust.

http://en.wikipedia.org/wiki/List_of_refrigerants


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## chaseonbase (Jul 31, 2013)

After seeing what they did to victor and the whole bathtub incident on breaking bad :shock: .... ya I dont want to be in the same county with HF.., but ignorance is bliss. :lol:


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## galenrog (Jul 31, 2013)

No, chaseonbase, when working with acids and any other chemicals ignorance is death.


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## niteliteone (Jul 31, 2013)

galenrog said:


> No, chaseonbase, when working with acids and any other chemicals ignorance is death.



If your lucky, 
The unlucky ones live maimed for life.


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## chaseonbase (Aug 1, 2013)

galenrog said:


> No, chaseonbase, when working with acids and any other chemicals ignorance is death.



:| im not referring to "ignorance is bliss" from a stand point of a person playing, using, creating constructing or handling harmful chemicals in manner that would cause harm to that person or any person in that vicinity. My father was a chemical engineer for over 37 years and told me horrifying stories about HF. When I stated I do not want to even be in the same county as that stuff. I was referring to the fact that I am most likely in the same county with that particular chemical. same as anyone else including those that may feel the same way as I do. Therefore with this being said my ignorance or there ignorance relating to the statement of not wanting to be in the same county and I and or there "ignorance is bliss".

I apologize in advance if I am coming across arrogant or a smart you know what. I just feel like when I make a comment on the forums I just have to be "extremely" specific on what I say or the context is misconstrued. I know when I ask questions people have been way nice in helping me find the info. I will admit that last post did come across half cocked and was taken the way it sounded. My personality can not be seen thru my text ,im general a pretty up beat guy and I enjoy a good laugh and like to kid alot, but I do my best to stay safe and use good practice even though it might not always be correct.


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