Gold partially covered with ironstone? see pic

[Floristweb]

Did a few minutes of digging around a quartz vein today; I ended up with this in the pan. It is heavy and gold in color. Hoping its gold but I haven't seen any posts about gold with ironstone attached to it. I am soaking it in CLR to see if it will eat off the iron. Does anyone know how long I should soak these little nuggets? If this is AU then I hope I have many days of finding it ;-) I spent at least 10 minutes digging around that quartz vein with a hammer, so if its real I'm pretty sure that would be a good take. What do ya'll think?

 

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[mytimetoshine]

Crush and pan.

 

[Floristweb]

Crush and pan.

Thought I'd try separating the iron first to see if I can get clean little nuggets. But I don't know if the CLR will do it it has removed quite a bit in the last half hour. have a few that are cleaning up. Sure hope it works, this way they'll have their natural shapes. Here's what it's starting to do..

 

[Floristweb]

Got impatient & decided to crush with pliers.... The black stuff turned to dust. I did get a few small specks of gold... but they were all small (no nuggets). But just finding a little was great. Hopefully I'll find more next time guess I better put a little more time into the hunt.

 

[huntsman53]

While there may be some fine Gold trapped in the specimens, it appears to be mainly Iron Pyrite!


Frank

 

[LP13]

Smash it with a hammer. If it's gold it will flatten out. If it's pyrite it will turn to dust. As far as gold being covered in 'ironstone' (assuming you meant magnetite), the process for gold depositing in a vein is one of precipitation from a hot chemical soup. That chemcial soup deep in the earth is like a pressure cooker with a lot of things in it like chlorine, sulfur, etc., which will dissolve gold especially when pressures are very high and temperatures are high. Once dissolved (along with a lot of other minerals) the hot water may rise closer to the surface and cool some, hitting a zone where it is cool enough to precipitate out. In this zone as it precipitates out, other minerals may also be precipitating (becoming solid like a crystal growing from solution), like quartz, magnetite, pyrites, copper, silver, etc. So the crack in the rock layer that it moved up into from below (often an uplift fracture, the vertical cracks you see in large rock deposits caused by stress relieving when part of the rock moves more than another part of it nearby) will eventually get filled up by all these minerals, with a particle of magnetite growing into a mass right next to a lump of gold or silver or whatever else is there.

 

[Floristweb]

Thanks for the info this is the spot I'm pulling material out of.

Smash it with a hammer. If it's gold it will flatten out. If it's pyrite it will turn to dust. As far as gold being covered in 'ironstone' (assuming you meant magnetite), the process for gold depositing in a vein is one of precipitation from a hot chemical soup. That chemcial soup deep in the earth is like a pressure cooker with a lot of things in it like chlorine, sulfur, etc., which will dissolve gold especially when pressures are very high and temperatures are high. Once dissolved (along with a lot of other minerals) the hot water may rise closer to the surface and cool some, hitting a zone where it is cool enough to precipitate out. In this zone as it precipitates out, other minerals may also be precipitating (becoming solid like a crystal growing from solution), like quartz, magnetite, pyrites, copper, silver, etc. So the crack in the rock layer that it moved up into from below (often an uplift fracture, the vertical cracks you see in large rock deposits caused by stress relieving when part of the rock moves more than another part of it nearby) will eventually get filled up by all these minerals, with a particle of magnetite growing into a mass right next to a lump of gold or silver or whatever else is there.

I'm getting this stuff from an area of saprolite with a solid mineralized quartz vein between saprolite above and below it. just down from this spot I've got hard stone that has been very visably fractured and lifted. Do you think I shoud try to break up the area where the frature is? I don't have a picture of that area but I'll snap one soon.

the odd magnetite, pyrite crystals are coming from the saprolite and when I crush them with pliers the pyrite and magnetite turn to powder- several also have small pieces of gold, but not all of them. Not sure what to do with this hillside next.

 

[Bonaro]

Pull a bigger sample and crush it all then send it through a blue bowl or carefully pan it. If there is gold it will show up.
If you want to try some nitric acid you should get a reaction on the pyrite and it should eat the iron (or manganese) coating off the gold but wont touch the gold
Gold does not shatter, pyrite does
If there is gold you will have to liberate it from the pyrite and other minerals. You can crush and separate with highly efficient gravity methods,or leach or flotation or amalgamation or you can smelt the ore.
No easy way out here

 

[Floristweb]

Pull a bigger sample and crush it all then send it through a blue bowl or carefully pan it. If there is gold it will show up.
If you want to try some nitric acid you should get a reaction on the pyrite and it should eat the iron (or manganese) coating off the gold but wont touch the gold
Gold does not shatter, pyrite does
If there is gold you will have to liberate it from the pyrite and other minerals. You can crush and separate with highly efficient gravity methods,or leach or flotation or amalgamation or you can smelt the ore.
No easy way out here

The idea of using nitric acid scares me. Can't that stuff explode? What would a highly efficient gravity method be? How would I go about getting a sample assayed? Is an assay expensive?

 

[Capt Nemo]

Nitric acid won't explode, but it can combine with other things to make explosives. Most also require sulphuric acid in combination to make the explosive.

In the aqua regia method, neutralizing the nitric acid with urea will create urea nitrate explosive. You should be able to destroy the explosive by burning, if I remember correctly. Urea nitrate is used as a shell filler and not for detonators from what I remember from my military improvised weapons class.

Just one of the hazards of mining!

 

[Bonaro]

I would do your own work first before paying for an assay. If you have free gold you can find it. If you have sulfide you will have to smelt it and just having to do that may make you choose a different place to dig because of cost and effort.

Acid, yest it can explode. More accurately, it can have a violent exothermic reaction. You have to be familiar with chemistry and the techniques used therein. For example, you don't pour full strength acid on your sample and wait for gold coins to fall out. This will lead to a stronger than necessary reaction. You combine your sample with distilled water then slowly add acid to the water to bring the concentration up to a point where it will start working. Acid can do other bad things like causing mercury to fume (poisonous). Long story short, you need some chemistry skills or at least be dedicated to learning some BEFORE you use acid.

High efficiency gravity method - There are various types of gold recovery devices that work based on the differences in specific gravity of the minerals involved. The types and relative efficiency are something like this:
Dry washers 70%
High bankers 80%
Dredges 90%
drop riffle sluices 95%
Spiral wheels 97%
Miller tables, jigs 98%
Hand panning 80-99%
Blue bowl 99%
(guys please, don't jump in a correct my numbers with your own opinions, I am generalizing for the purpose of comparison)
The discussion about fine gold recovery would take a loooong time and there are many more devices than the ones I listed.
Notice that as recovery gets higher the difference in % narrows. Any gravity based device can recover that match head nugget without much effort. The fine gold is where the values are. In general, when your recovery method increases in efficiency, the production rate goes down. The blue bowl does a great job at catching super fine gold but you have to feed it with a table spoon.

This is where I preach about panning skills. I have watched people pan so poorly that they could wash out a pennyweight nugget and leave frustrated because there was no gold in the stream. You must possess good panning skills. Panning by hand is the last step in any gold mining operation. Without going too far off in the weeds on this topic. For your situation I would crush everything the run it through a small drop riffle sluice. Take the concentrate from that and carefully pan it. You should see at least most of the visible gold present. Now consider the amount of gold you recovered vs. the size of the original sample to determine if you want t o take a closer look and get a full assay.

 

[Floristweb]

I would do your own work first before paying for an assay. If you have free gold you can find it. If you have sulfide you will have to smelt it and just having to do that may make you choose a different place to dig because of cost and effort.

Acid, yest it can explode. More accurately, it can have a violent exothermic reaction. You have to be familiar with chemistry and the techniques used therein. For example, you don't pour full strength acid on your sample and wait for gold coins to fall out. This will lead to a stronger than necessary reaction. You combine your sample with distilled water then slowly add acid to the water to bring the concentration up to a point where it will start working. Acid can do other bad things like causing mercury to fume (poisonous). Long story short, you need some chemistry skills or at least be dedicated to learning some BEFORE you use acid.

High efficiency gravity method - There are various types of gold recovery devices that work based on the differences in specific gravity of the minerals involved. The types and relative efficiency are something like this:
Dry washers 70%
High bankers 80%
Dredges 90%
drop riffle sluices 95%
Spiral wheels 97%
Miller tables, jigs 98%
Hand panning 80-99%
Blue bowl 99%
(guys please, don't jump in a correct my numbers with your own opinions, I am generalizing for the purpose of comparison)
The discussion about fine gold recovery would take a loooong time and there are many more devices than the ones I listed.
Notice that as recovery gets higher the difference in % narrows. Any gravity based device can recover that match head nugget without much effort. The fine gold is where the values are. In general, when your recovery method increases in efficiency, the production rate goes down. The blue bowl does a great job at catching super fine gold but you have to feed it with a table spoon.

This is where I preach about panning skills. I have watched people pan so poorly that they could wash out a pennyweight nugget and leave frustrated because there was no gold in the stream. You must possess good panning skills. Panning by hand is the last step in any gold mining operation. Without going too far off in the weeds on this topic. For your situation I would crush everything the run it through a small drop riffle sluice. Take the concentrate from that and carefully pan it. You should see at least most of the visible gold present. Now consider the amount of gold you recovered vs. the size of the original sample to determine if you want t o take a closer look and get a full assay.

Thanks so much. I will try to crush/sluice/pan some next weekend. How much AU would you hope to find per gallon of crushed Quartz before having an assay?

 

[KevinInColorado]

There's about 200 gallons of crushed ore to make a ton and 3 grams per ton is enough to get most people interested so 3/200 =0.015 grams aka "not much". However even not much looks like a lot in a finished pan of finely crushed ore...as I hope you soon see!