Spotting Valuable Mineral/Ore Bearing Rocks?

[Wint]

Hello everyone,

I had a question about spotting valuable mineral/metal bearing rocks (gold, silver, etc.). I see people throwing around Galena, and Chalcopyrite and such.

Is there a cheat sheet out there with pictures of what these potentially valuable stones look like in their natural state? ie, covered in years of weathering and such? I would love to keep my eyes peeled when I am out hiking, but I would be a liar if I said I had any clue what I was looking for.

I am not talking about all the pictures where folks are holding a chunk in their hand, I am talking about what this stuff looks like before it is even scratched, still in the boulder or rockface.

Any and all info is appreciated!

 

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[russau]

There was (?) a website in Colorado that had a sub - column about minerals that I used to go to (Coloradoprospector.com ) (Dan Shafer) But the owner dies a few years back and I don't know if his wife (Denise) ever kept it running since Dan's passing. YEP they are still up-n-running ! I hope I'm NOT violating any rule !!! But go to their site and look for the "welcome to the kids page" then scroll down to "Minerals by name. all the minerals are listed alphabetically and when you click on a certain mineral there is several color picture's of it but you need to look for it on that page .I found it very helpful back in it's time ! Good Luck and enjoy ! AND WELCOME TO THE SITE !

 

[tamrock]

To me its important to know and understand what's going on with the geologic formations your around when prospecting. A good simple understanding of what's taken place in the rocks and how they were formed can tell you a lot about the potential of possible mineralization. Contact zones and hydrothermal replacement are things I look at when I'm driving down the road in the mountains. Ancient alluvials are some of the things that interest me when I'm in the field. I've lived and traveled in the mountain west for many years now selling mining supplies and I'm always keeping an eye on the rocks around me, just for general interest. I've always liked rocks I guess as far as I can remember. These roadside geology books give a good basic understanding of formations and I believe some history of mining activities which are always good areas to look around. https://geology.com/store/roadside-geology.shtml

 

[russau]

Lot's of info in these books! Thanks for the post !

 

[Wint]

To me its important to know and understand what's going on with the geologic formations your around when prospecting. A good simple understanding of what's taken place in the rocks and how they were formed can tell you a lot about the potential of possible mineralization. Contact zones and hydrothermal replacement are things I look at when I'm driving down the road in the mountains. Ancient alluvials are some of the things that interest me when I'm in the field. I've lived and traveled in the mountain west for many years now selling mining supplies and I'm always keeping an eye on the rocks around me, just for general interest. I've always liked rocks I guess as far as I can remember. These roadside geology books give a good basic understanding of formations and I believe some history of mining activities which are always good areas to look around. https://geology.com/store/roadside-geology.shtml

I've got the CT/RI Roadside Geology book sitting in my Amazon cart for Prime day next week. Appreciate the info!

 

[Joanne]

I've got the CT/RI Roadside Geology book sitting in my Amazon cart for Prime day next week. Appreciate the info!

I have the Nevada version on my bedside table. General geology books are great, but ones that point out local features are a great learning tool.

Joanne

 

[Moesia]

If you are referring to gems they do not weather (for the most part). As for the metallic minerals they really poke the eye, so you are not likely to just walk over them and not notice. The most likely problem is that almost all minerals that you would show interest in are all covered beneath some level of dirt, mud, etc. Walking around and just looking randomly at the ground is almost fruitless exercise. Not because you do not know what you are looking at (wast majority of "valuable" minerals look nothing like the "common" minerals that you have no interest in, again they would immediately catch your eye), but because those minerals are so eye catching even in weathered condition that the people who have been inhabiting the land thousands of years before you, wherever you are now, have picked it up from the surface and taken it. You are almost in no danger that you are just gonna pass over some natural treasure because you did not know what you were looking at. Once you learn what the eight or so "common" minerals look like in all their variations (it takes very little practice if you do not know), you are going to be set.
You are going to have more trouble with the id once you find something that does not fit with the crowd so to say. But that too can be overcome with diligence in time.

 

[Mad Machinist]

"Conventional" geology is being turned on it's head right now. Things are being found that are not supposed to exist in places that they are not supposed to be found.

Look at the La Paz district in Arizona. Rare earth metals, yet geologists swore up and down that they don't exist here. Same thing for Round Top Mountain in Texas.

As Tamrock said, learn a little about how rocks and fault lines form. The "lay of the land" is a good place to start. Many times fault lines and mineral deposits will follow "ridgelines". Those will be your greatest ally in looking for minerals. And when in doubt have it tested.

 

[Moesia]

"Conventional" geology is being turned on it's head right now. Things are being found that are not supposed to exist in places that they are not supposed to be found.

Look at the La Paz district in Arizona. Rare earth metals, yet geologists swore up and down that they don't exist here. Same thing for Round Top Mountain in Texas.

You bring this up again, care to elaborate? Who? How? Is there a place to get informed, read up? I am certainly interested to get educated.

 

[BlasterJ]

The ICMJ journal did an article a couple of months ago on Copper prospecting. It was written by a pretty well-known exploration geologist, and he points out how a lot of good Copper deposits often present as white on the surface, even if the minerals are normally green or blue before weathering. So it's not 100% that metallic ores will catch the eye.

I recommend getting a subscription. If you also get the on-line access, you can browse many years of the old articles:

https://www.icmj.com

Note that this is a shameless plug, as they just published my blasting article in the November issue.

 

[galenrog]

Good prospectors learn how to test for various metals and minerals in the field. There are numerous guides available. Eyeballs are not enough.

 

[Moesia]

The ICMJ journal did an article a couple of months ago on Copper prospecting. It was written by a pretty well-known exploration geologist, and he points out how a lot of good Copper deposits often present as white on the surface, even if the minerals are normally green or blue before weathering. So it's not 100% that metallic ores will catch the eye.

I recommend getting a subscription. If you also get the on-line access, you can browse many years of the old articles:

https://www.icmj.com

Note that this is a shameless plug, as they just published my blasting article in the November issue.

Congratulations, it is a noble thing to reach a height in your profession where you can enlighten others.
No, it is not 100%, but all things in life are such. Alteration such as "white on the surface" is not the thing he is going to take home with him. He confessed that he is a beginner on the subject. It would be hopeless for him to go look for valuable minerals by tracing top soil alteration. To him many things would be white or yellow or red, etc. My first post may not be elaborate, but it is the best advice for someone that has no experience on the subject. All Wint can do is read some basic books on geology and collect a few rocks to start to learn to recognize the "common minerals".

 

[russau]

The icmj journal is the BEST mining info available ! Do yourself a favor and subscribe to it !

 

[Rail Dawg]

One thing that helped me was a mineral sample tray. The one I got had 75 minerals from talc all the way up to the heavy stuff. Labeled real nice.

Looking at the minerals under magnification and studying their structure is a great learning tool.

I still look at it to refresh.