How do you find deposits?

[Customx_12]

How do people know where to build mines for gems? I don't get how they can find large deposits just by looking. Is it all a big fishing game or is there a technique I'm not aware of?

 

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[woof!]

Knowledge of geology and minerology, use of effective prospecting methods, diligence and hard work. Rarely "just by looking" or just by luck.

--Dave J.

 

[Eu_citzen]

I think Dave summed it up pretty well.

 

[Customx_12]

Knowledge of geology and minerology, use of effective prospecting methods, diligence and hard work. Rarely "just by looking" or just by luck.

--Dave J.

Can you elaborate as this really was the basis of my question?

 

[Bajahunter]

Ok I'll take a shot at this. First, your question does not have a single answer. It depends on what you are looking for and where you are looking for it. Here is an example of Woof's well stated reply. Knowledge Lets say you are prospecting for gold. You need to know what other rocks it associates with, what they look like and are they found where you are looking. Effective prospecting methods Do you know how to use a gold pan, rocker box, or sluice? You wont find anything if you don't know how to use the equipment correctly and know what to look for. You don't find diamonds the same way you find gold. Your method will depend on what you hope to find. Diligence You might have to cover a lot of ground to find a spot worth working. Personally I just like to go for hikes and try to understand my local geology. I don't go prospecting, I just keep an eye out for interesting rocks. If I see something interesting I will go back later for a more in depth look. If there is something specific you are looking for maybe we can be of more help, but to answer your question as asked, would require a book length reply. Rob

 

[Customx_12]

Ok I'll take a shot at this. First, your question does not have a single answer. It depends on what you are looking for and where you are looking for it. Here is an example of Woof's well stated reply. Knowledge Lets say you are prospecting for gold. You need to know what other rocks it associates with, what they look like and are they found where you are looking. Effective prospecting methods Do you know how to use a gold pan, rocker box, or sluice? You wont find anything if you don't know how to use the equipment correctly and know what to look for. You don't find diamonds the same way you find gold. Your method will depend on what you hope to find. Diligence You might have to cover a lot of ground to find a spot worth working. Personally I just like to go for hikes and try to understand my local geology. I don't go prospecting, I just keep an eye out for interesting rocks. If I see something interesting I will go back later for a more in depth look. If there is something specific you are looking for maybe we can be of more help, but to answer your question as asked, would require a book length reply. Rob

Seems you missed something in my question. I specifically asked about gems. I go gold prospecting very often and am interested in looking for gems as well. The second half of your response seems to be more appropriate for what I asked. I own a chunk of land in the San Diego county area as well as a chunk near San Luis Obispo. In the San Diego area, I know a lot of tourmaline has been found. How does one know where to start building a shaft to search for deposits?

I don't get why I seem to be getting attitude about what seems like an innocent question. Metals can be found with detectors and ground penetration techniques. I'm wondering what the method is for finding gems. That's it. It's not a trick question. If people don't know, either don't respond or just say "I don't know". But the rudeness is really uncalled for. (This is not specifically directed toward you, Baja.)

 

[Bajahunter]

I am sorry you think we are giving you an attitude. I certanly wasn't trying to give you any grief. I don't think anyone was rude in their response..
You are not going to dig a shaft "looking" for tourmaline, you dig a shaft when you have a good idea something is there.
In some ways your question is very naive, in other ways it is very complex. It is not as simple as you want to make it.'
If you ever find an answer to your question please post it here.
Rob

 

[Customx_12]

I am sorry you think we are giving you an attitude. I certanly wasn't trying to give you any grief. I don't think anyone was rude in their response..
You are not going to dig a shaft "looking" for tourmaline, you dig a shaft when you have a good idea something is there.
In some ways your question is very naive, in other ways it is very complex. It is not as simple as you want to make it.'
If you ever find an answer to your question please post it here.
Rob

At the end of my comment, I pointed out that it wasn't you. Rather, it was primarily the first response that seemed simplistic, short, and snippy. Of course my question is naive otherwise I wouldn't have asked it. I don't know the answer. I'm ignorant and naive on how to find gem deposits. I'm trying to figure out how it's done and I don't usually have a hard time understanding complex processes. You tell me that "you dig a shaft when you have a good idea something is there". So my question, again, is: how do you know something is there? What gives you the good idea that something is there? How can you tell if there is a large mineral deposit in the middle of a hillside just by looking at the outside? Is there always geological evidence on the outside that indicates what's on the inside? If not, what tools, techniques, or processes can you use to see what is on the inside?

 

[woof!]

Knowledge of geology and minerology, use of effective prospecting methods, diligence and hard work. Rarely "just by looking" or just by luck.

--Dave J.

Custom, there is no "the answer". We're not holding out on you.

If your inquiry is about finding possible gems on property you own, you need to get out there and cover it thoroughly on foot. However for that to do any good, you need to know how to identify rocks and minerals, geological formations, and to visualize the geological processes that led to the present conditions.

"Effective prospecting methods" depends on the nature of the site, the kinds of things you're looking for, how much time you've got, and how much money you've got. There are many. There is no method specific to locating "gems" in the ground where they are not already known to exist, since "gems" are many different kinds of things that form in many different rock types and geological settings. Where they are already known to exist, the most common method is pick and shovel; or if running water is available, sluicing and panning.

If by "gems" you include semiprecious stones, such are of widespread occurrence and there's a good chance such are to be found on your property if it's rocky (as opposed to riverbottom silt for instance). If all you want to do is a little rockhounding as a hobby that's one thing. However when you talk about sinking shafts into the ground that's an economic activity which requires capital investment and dealing with government regulations. And, unless you're mining investors rather than gems, you've gotta have enough gems and you have to know how to sell them at a price high enough to cover your costs. Mining is hard dirty work and there are a lot more ways to lose your shirt doing it than there are ways to make money at it.

If dreams of gem mining have bitten, you've got years of book-learning and research and listening to old-timers ahead of you. Plus hard work and getting dirty. You might also join a local rockhounding club where other members can give you a bit more information on local geology and show you some rocks and minerals to give you some practice identifying them.

--Dave J.

 

[Bajahunter]

On my first post I asked what you were looking for and we could be more specific. Then when you said you were interested in Tourmaline in California I didn't give any specific advice.

What gives you the good idea that something is there? How can you tell if there is a large mineral deposit in the middle of a hillside just by looking at the outside?
Tourmaline s are found in granite and granite pegmatites and in shist and and marble. You need to look for those kind of rocks. You can't really tell what is inside the hill without a lot of work.

Is there always geological evidence on the outside that indicates what's on the inside?
Not always. Look at the existing tourmaline deposits in your area. See how it relates to the rocks over it and under it. Get a geologic map for your area. It will show the surface rock in your area and the layers of rock underneath. They already know what types of rock you are sitting on, just not if there are gems there.

If not, what tools, techniques, or processes can you use to see what is on the inside?
That would be digging, boring, seismic mapping. That's the part that takes time and money.
Rob

 

[Customx_12]

Thank you, thank you, thank you! The last two posts were the types I was looking for.

 

[jgleaves]

check out this web site.

Mineralogy Database - Mineral Collecting, Localities, Mineral Photos and Data

It has a wealth of info but you will have to search thru it for specific San Diego info. You can also locate "localities" that are current or former mining sites. Maybe find one close to your land. I live in San Diego and look for tourmaline on more than a few occasions. Where is your land located ? ALso, it is hotter in summer in the hills now. Good luck.