# Separating gold from quartz



## Agmix (May 5, 2017)

Hi to all !
This is my first post to this forum and i hope i will describe my "problem" correctly

I start to play with gold flakes that i filtered from river sand.
It's actually a mix of 60% quartz and 40% gold.
I can filter it to 50/50 or 40/60 but quartz will always be in this mix 

Question:
if i melt this mixture with borax, what will happen ?
Will quartz melt with the gold into one compound ?

Anyhow, what would be the best way to separate quartz form gold.
I dont want to use HF acid...

A.M.


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## g_axelsson (May 5, 2017)

Quartz and gold should be easy to pan to get rid of the quartz.

50% gold mixture isn't a problem to melt directly, that's enough to separate and get the gold to melt together.

But from your description I'm not totally convinced that you actually have gold. Pyrite and mica is often mistaken for gold and is a lot harder to separate, but if it melts together into a metallic blob then it was probably gold.

Göran


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## Agmix (May 5, 2017)

Thank you for reply.

According to the structure of flakes, it looks like its gold and i can melt it with burner.
As far as i know "fools gold" does not look as flakes , it's more sand like...

Quartz and gold should be easy to pan to get rid of the quartz.
** The problem is that quart flake is a bit bigger than gold and it looks like it have the "same" weight.
Am not pan/gold expert so until i learn this i will try alternative methods  

Btw. tell me, how to check if the gold flake is real gold ?
Is this flake "conductive"  ? 
I have tested with strong magnet and there was no iron or magnetic in this mix...

So , you are suggesting that i burn altogether...
Ok. i will try.

A.M.


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## anachronism (May 5, 2017)

Fools gold is brittle, gold is malleable. If you crush one it will shatter, the other will deform.


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## g_axelsson (May 5, 2017)

Mica comes in flakes and is hard to separate from quartz in a pan, it is sometimes mistaken for gold.

If you want a good tip on learning to pan, put a tiny piece of lead in the pan. If the lead is still there when you finish off panning then the gold should also be there. If the gold comes in flakes, flatten the lead so it has the same form and it should behave similar to any gold.

Göran


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## Agmix (May 5, 2017)

I try to melt this but i fail.
I have used gas torch and gold mix was in iron mold.
I can see that the mix changed the colour to red but i could not melt it .
After 10 minutes i give up...

BTW. i forgat to write that i didn't use any borax, just plain gas torch...

How long should i try to melt this mix ?

A.M.


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## FrugalRefiner (May 5, 2017)

Agmix said:


> I try to melt this but i fail.
> I have used gas torch and gold mix was in iron mold.
> BTW. i forgat to write that i didn't use any borax, just plain gas torch...
> How long should i try to melt this mix ?


You shouldn't try to melt it all in an iron mold. Gold, and many other metals, will alloy with iron. If you do/did have gold, and you had succeeded in melting it, the molten gold would have dissolved some of the iron it was in contact and made a real mess.

The best way to melt gold is in a melting dish, a shallow bowl shaped dish made from clay, silica, or some similar material that the gold will not blend with. In a pinch, you can use a piece of charcoal with a hollow area carved into it. If you're desperate to melt it, you can use a piece of drywall or a block of wood. Only use these while you're waiting for a melting dish to arrive.



> I can see that the mix changed the colour to red but i could not melt it .
> After 10 minutes i give up...


That's not a good sign.


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## Agmix (May 5, 2017)

OK. i will try your suggestions regarding melting technique.
-------------------------------
That's not a good sign.
*** i was thinking about that too, but i guess we can not be fully sure until i try it.
What can be worst case scenario ? That all this is mica ?

I forgot to write that i try one other option for separating quartz from gold (or what that is ) and this was quite good one, but i didnt have more H202. Shortly i have put 30% H202 into this flakes mix and after one day, mostly all quartz was dissolved and the the rest was on the bottom of plastic box, while the "gold" was floating.

After i separate the gold with pipette and wash it, flakes have drooped down in the box full with water...
This is the flakes that am using for test.

Btw. would not mica also dissolve, like quartz ?

One more thing, after all that heated up i spill it in cold water.
As far as i understand, mica is mineral and i this temperature change would force it to break ?

Few photos of purified and not purified mix:
https://ibb.co/h5Jed5
https://ibb.co/bLcuBQ
https://ibb.co/iE3ed5

A.M.


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## g_axelsson (May 5, 2017)

H2O2 doesn't dissolve quartz so then the quartz wasn't quartz either.

The rest looks like mica to me.

Göran


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## Agmix (May 6, 2017)

Hi. 
It didnt disollve it completely, the mix just separate. Quartz stayed on the bottom.
Am pretty sure that this is quartz because they are digging for sand there and this river is full of it.
They are also selling this as "quarz sand"...

Mica or not:
- am also not sure. I think that the only option is to burn this and try to break it after ?
Is there some simple chemical test that can be used to "color" the gold flakes ?

A.M.


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## g_axelsson (May 6, 2017)

If you crush mica you will get a white powder. It might be colored by iron so it would look like a yellow powder, but washing it in an acid (HCl, oxalic acid, citric acid...) will remove the iron and only leave the white powder.
Crushing gold is really hard since as anachronism pointed out, gold is malleable and will only deform and smear.

Crush a grain with a flat nosed pliers, if it is crushed it wasn't gold, if it just flattens out it's probably gold.

Dissolving gold in aqua regia would also work, but if there are a lot of silver mixed in then the dissolving might not go to 100% as the grains get encrusted in silver chloride. The liquid could then be tested for dissolved gold with stannous chloride.

You can also test if the flakes is conductive, in other words, if they conduct electricity. It's easily done with a multimeter with the "beep test". I've used this method for small grains in rocks a long time ago when I started collecting minerals.

Göran


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## Agmix (May 6, 2017)

Thank you for your suggestions and support.

Conductivity test was my first test, but i was thinking that there is to big resistance so it can not be measured.
Now that i think a bit more, if there is a gold this test should pass anyhow....
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Before burning, i tested for magnetism with big neodimium magnet.
Nothing happened. After burning in clay pot ( nothing melted ) the "gold" flakes turn into silver / dark brown.
The funny part is that those flakes are now very, very low magnetic. 
So now am confused. Those flakes ware gold alike and few of them gold brown. 
------------------------------------------------
There is still no conductivity in those flakes but like i wrote, they are semi magnetic.
What kind of material is this ? Some ferrite ?

A.M.


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## g_axelsson (May 6, 2017)

My guess, mica flakes colored by iron hydroxides so it looks yellow to brown depending on how much there is. The heat drives off water and creates iron oxides, Fe2O3 is magnetic. That would both affect the color and the magnetism of the flakes.

Gold is a very good conductor so a test should show it like a short circuit. Gold is used as wires connecting IC:s to the pins and those wires are thinner than a hair.

Göran


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## everydayisalesson (May 6, 2017)

Im with Goran on this one. It does not look like gold, it does look like mica.

I would hammer it. If it turns to powder, its mica. If it just spreads out, it might be gold.

Mike


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