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had my share of busting rocks i thought could have contained gold. on a scale of 1-10 which of these would you guys think would have gold.       sometimes iv'e felt like i'm working on a chain gang.

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None of them. None seem to be any type of ore that I am familiar with.  All are various type of rock. 

 

The second to the last one might be getting close to looking like ore. Hard to tell from the photos. Oxidized hematite is what has free gold in my neck of the woods.

Edited by Bedrock Bob
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This is classic gold ore.

The rock on the left represents where the vein becomes more solid and mineralized. It contains less gold and much more silver, copper and base metals. The gold is generally to the side of the vein against the country rock distributed in fine particles in the hematite.

The rock on the right has more quartz and the quartz is filled with oxidized minerals. It has more gold. The gold is in the teeth of the quartz as well as against the country rock. There is more, coarser gold in this type of gossan than in the denser, darker one on the left. As a general rule the gold gives way to silver and copper as the vein has less iron and gives way to base metals. The gold generally sticks with the hematite and really oxidized zones.

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These samples both show visible gold and were within three feet of each other on the same vein as it pinched and swelled. The ore on the left was in the pinch and on the right in the swell. You can actually see a particle of gold in the ore on the left. It is on the bottom near the ball of my thumb. The photo came out nice and you can zoom it well enough to actually see visible color. I can not see any gold in the rock on the right but this section of the vein is always richer.

In areas with free milling gold it is fairly easy to find ore that you can pan. Not to say gold could not be in any rock because I suppose it could be. But as far as crushing and testing rock I would advise to stick to mineralized zones where you can pick up oxidized hematite and quartz gossan.

Hope this helps.

Bob

Edited by Bedrock Bob
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thanks for the pics  and explanation Bob.  i have seen a lot of rock like that.  don't have a rock crusher yet. does quartz gossan mean the quartz is colored or next to gossan.  have heard dirty looking quartz is best? true?

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30 minutes ago, Bedrock Bob said:

This is classic gold ore.

The rock on the left represents where the vein becomes more solid and mineralized. It contains less gold and much more silver, copper and base metals. The gold is generally to the side of the vein against the country rock distributed in fine particles in the hematite.

The rock on the right has more quartz and the quartz is filled with oxidized minerals. It has more gold. The gold is in the teeth of the quartz as well as against the country rock. There is more, coarser gold in this type of gossan than in the denser, darker one on the left. As a general rule the gold gives way to silver and copper as the vein has less iron and gives way to base metals. The gold generally sticks with the hematite and really oxidized zones.

DSCN0376.JPG

These samples both show visible gold and were within three feet of each other on the same vein as it pinched and swelled. The ore on the left was in the pinch and on the right in the swell. You can actually see a particle of gold in the ore on the left. It is on the bottom near the ball of my thumb. The photo came out nice and you can zoom it well enough to actually see visible color. I can not see any gold in the rock on the right but this section of the vein is always richer.

In areas with free milling gold it is fairly easy to find ore that you can pan. Not to say gold could not be in any rock because I suppose it could be. But as far as crushing and testing rock I would advise to stick to mineralized zones where you can pick up oxidized hematite and quartz gossan.

Hope this helps.

Bob

Well hold on a minute.  Are you sure one of those (you pick) isn't a meaty-o-right?  You said they were found within feet of each other, but they look so different.  One of them must have come from space !!  :4chsmu1:

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I see a few conglomerates there (pics 8, 9, and 12). Conglomerates of course are sedimentary rocks. If the sediments they formed in contained gold, then these rocks would also. That is, however, highly unlikely.

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48 minutes ago, JOHNM said:

thanks for the pics  and explanation Bob.  i have seen a lot of rock like that.  don't have a rock crusher yet. does quartz gossan mean the quartz is colored or next to gossan.  have heard dirty looking quartz is best? true?

Yeah. Dirty. Stained with iron. Just like the one on the right. You can see the quartz go from white to a deep rusty auburn color in the lower right corner of that rock. Dirty quartz stained with iron. That is what they are talking about when they say "dirty quartz". When you crush it it will turn your water to thick red toxic enchilada sauce.

Gossan is just how an oxidized hematite ore is described. I am not sure where the quartz stops and the gossan starts. The whole formation is a gossan to me. I suppose my lingo may not be completely accurate though.

This one was about two feet wide and ran along a contact between andesite and diorite. It was generally a "red" line in an outcrop that had several small shafts driven along it and a big tunnel driven below. The miners obviously located free milling ore in the little test holes along the vein as it ran up the hill and dug the tunnel at the foot of the hill to haul it out from below. So I worked the surface between the test holes. A classic way of scrapping for hardrock ore and hunting "pockets".

The best looking quartz is any color with gold in it. Find gold with your loupe first and THEN crush. Most guys crush a bunch of rock and then try to find gold in it. IMHO that is approaching it backwards. I always get a visual on free gold before I go to the effort of crushing any rock. If it is worth crushing you will be able to see a speck or two once in a while. Once you have familiarized yourself with the ore and can pretty much tell what is going to have some gold in it THEN start collecting and crushing it. 

Edited by Bedrock Bob
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1 hour ago, LukeJ said:

Well hold on a minute.  Are you sure one of those (you pick) isn't a meaty-o-right?  You said they were found within feet of each other, but they look so different.  One of them must have come from space !!  :4chsmu1:

Don't make me post another puppy Luke.  :)

I am trying not to think about him tonight... All alone, tied to that tree beside the road. I hope he will be O.K.  I'm getting all misty eyed thinking about it. I just hate it when that happens. :cry2:

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49 minutes ago, Bedrock Bob said:

Don't make me post another puppy Luke.  :)

I am trying not to think about him tonight... All alone, tied to that tree beside the road. I hope he will be O.K.  I'm getting all misty eyed thinking about it. I just hate it when that happens. :cry2:

You know darned well he'll chew through the rope and be sleeping on the front porch by morning. 

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7 hours ago, d_day said:

I see a few conglomerates there (pics 8, 9, and 12). Conglomerates of course are sedimentary rocks. If the sediments they formed in contained gold, then these rocks would also. That is, however, highly unlikely.

There is a small placer near where I live that has gold deposited in Gila conglomerate. It’s pretty crazy how gold gets deposited sometimes.  I would have never thought it would be a good area to work but the old timer drywasher piles proved different. 

Edited by Desertpilot
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3 hours ago, Desertpilot said:

There is a small placer near where I live that has gold deposited in Gila conglomerate. It’s pretty crazy how gold gets deposited sometimes.  I would have never thought it would be a good area to work but the old timer drywasher piles proved different. 

Likewise there is a fossil placer near Ribera, New Mexico in sandstone. But that is not hardrock ore and that is the question the OP was asking I believe.

Placer is one thing and hardrock ore is something entirely different. Sure there are plenty of buried placers that are in a cemented strata. And those strata can become fossil placers over time. But my interpretation of the OP's intent was to visually identify gold ore in a lineup. Of which there are no photos at all as far as I can see. None of the rocks posted are likely sources of free milling gold. Not to say that some could not have gold in them, but none are the type of rock that a prospector would crush and expect to find any.

The only visual indications a prospector would have that any rock might contain gold (other than visible gold particles) is mineralization. None of these rocks show the type of mineralization associated with gold. I think that was the purpose of the post was to learn what ore looks like. Placer could possibly be anywhere but ore is specific and easily distinguishable from the type of rock posted. 

We can't expect to find hardrock gold ore if we look at every rock that could possibly contain particles of placer. We must limit our examination to rocks that it is likely to be in or that it is known to be in. That narrows the search in 90% of all southwestern gold bearing areas to oxidized hematite gossan with quartz. That is the very best and the only material to be considered for the novice hardrock prospector unless production records indicate otherwise.

Just my two sheckles worth. 

Edited by Bedrock Bob
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