Friday, February 11, 2011

Characteristics of Gold-Bearing Quartz Veins (Part 1)

(Iron-stained or "rusty" quartz like this is a common gold-bearing vein material.)

The single most common gold-bearing matrix in the world as a whole is the quartz vein. I'm no geologist, but as a hard-rock or placer gold miner I do know that having a basic understanding of the geological characteristics of auriferous quartz veins is important. So here goes:

Sulphides and Chemical Oxidation

Most gold-bearing quartz veins and stringers (Note: Small or very thin veinlets of quartz. J.R.) will contain at least some minor sulphide minerals as part of their composition. One of the most common sulphide materials is iron pyrite, or FeS2, a form of iron sulphide resulting from the chemical oxidation of the iron inherent to this material.

Quartz veins that contain iron sulphides or oxides are pretty easy to spot since they will display a yellow, orange, red, or reddish-orange coloration. This "rusty" look is just that and it is very similar to the colors found when when old iron is left outside in the elements to rust and oxidize.

"Country Rock" or Host Rock

Typically (but not always) these sulphide quartz veins are found along or near major geological faults or in areas where large tectonic processes may have occurred in the distant past. The quartz veins themselves will often be fractured or "crosscut" in any number of directions and it is at these junctures, fractures, or crosscuts that the greatest amounts of gold will be found.

You've heard me talk elsewhere about "country rock" or host rock, which is the most prevalent underlying rock (including bedrock) in any given gold-bearing locale. In areas where auriferous quartz veins are found some of the most common host rocks are:

Schist (especially green schist);








and various forms of Metamorphic volcanic rock.

Let's Talk About This Last One

Let's talk about this last one for a moment. Many newcomers to gold mining or those with little knowledge about the processes involved in gold mineralization automatically assume that any area displaying volcanic activity (lava beds, etc.) will contain gold.

WRONG! Areas or locations with recent (geologically speaking, that is) volcanic activity seldom contain gold in any concentrations at all. The term metamorphic means that some sort of significant chemical and/or geological changes took place over time that altered that original volcanic host rock into something altogether different. (Note: Metamorphics, by the way, form some of the best gold ground in the American West and Southwest. J.R.)

Shale, Limestone, and Carbon

Geologists also say that areas containing shale, carboniferous (carbon-bearing...coal is carbon but I don't think they mean coal per se), and limestone country rock can also host gold-bearing quartz veins. Okay, they are the experts and I have great respect for the science of geology and those who practice it, but I will tell you something here and

In over three decades of small-scale gold mining I have yet to find a single grain of gold in areas containing these types of country rock. However, I have prospected areas here in New Mexico where rich Metamorphic gold ground exists just a few miles away from fairly large areas of shale, limestone, and carboniferous host rock. So, the geologists are on to something.

That's it for this round. There's more to come so stay tuned...

If you liked this post, you may want to read: "Hard Lessons: What I've Learned in 30+ Years as Small-Scale Gold Miner (Part 5)"

(c) J.R. 2011

Questions? E-mail me at:


  1. The veins near the surface of the skin are called superficial veins. The veins that are deeper and closer to the center of the body are called deep veins.


  2. Thanks for the info Evan. Jim

  3. The country rock here in the "gold belt" here in Tennessee is typically shale or siltstone, which has been intruded by quartz veins and stringers of hydrothermal origin, and the quartz veins do contain gold. Maybe not of commercial significance, but plenty for the recreational / small scale miners.

  4. That's valuable info you've passed along Allen. Thanks for commenting. J.R.

  5. Well, now I've got more to think about. Theres quite a bit of quartz around here, some looks rusty.Guess I'll have to crush some and see.... Thanks again Jim, Allways interesting.

  6. You're more than welcome my friend. Keep coming back! J.R.

  7. Interesting, JR. My wife and I were just discussing (other than spending more money on more toys) taking a look at the area around and south of Quay, NM, where the mesa rises up as you head further south. That there have been few placer claims in eastern NM is interesting, considering that there are two KNOWN ancient volcanic events there, and that there is ample quartz and alluvial material there. I haven't worked that area before, but since no one else is, it really looks like a good spot to burn off a weekend or two.

    Take care...

  8. Sounds like a plan Mountain! Let me know what you find out. Best, J.R.

  9. In or near an area of metamorphic host rock with my metal detector, using a low threshold noise, set to go silent over mineral and make a sound over metal. I found a narrow quartz vein heavily burdened with Galena, an ore of lead, with a rust colored oxidation on one side. At first I considered it to be Iron Pyrites but on careful inspection I found it to be gold. The gold is fine on and within the surface but it has been their allowing me to high grade it for years. Richard

  10. Thanks for letting us know about this. Yes, galena is a common lead ore with association with silver. Getting gold with galena is not common, but sounds like you hit something good. Best, J.R.

  11. Hi Jim,
    I'm a beginner at gold prospecting but ravanius for information about it. I live in the Northeast and work in Westchester County, NY. At my work place is bed rock all around. It looks as though it were the result of lava flow. Sheets of granite rolling atop each other. In the midst of the granite is a thick vein of quartz and it is covered with dark red/brown coating. Can I make an assumption that the likelihood of gold is beneath the surface of the quartz or might it be deeper down in the granite?

  12. Well, you can make that assumption but I doubt you'll find any gold there. New York has no historical production of gold (placer or lode) that I'm aware of. That said, it never hurts to look.

  13. I have permission to pan a creek in southern Illinois that runs through a old coal mine , huge coal mine the creek is littered with all kinds of stuff I'm very anxious to see if I find gold jefferson county very close to the edge of the old glaciers from Canada. .Placer gold.. my curiosity is since all the land is from the mine from the late 70s is that the Placer gold from the destroyed land is all in the gravel bars by now.. any input on my idea?

  14. Typically placer or lode gold is NOT found with coal or in that type of geology. However, glacial activity is another thing altogether. I'd forget the coal mine idea and start researching the glacial till in your area. Best to you!

  15. Finding prospecting for {url= }lode deposits of gold{/url} is not the relatively simple task it once was because most outcrops or exposures of mineralized rock have been examined and sampled. Today's prospector must examine not only these exposures, but also broken rock on mine and exposures of mineralized rock in accessible mine workings. Gold, if present, may not be visible in the rock, and detection will depend on the results of laboratory analyses. Usually, samples of 3 to 5 pounds of representative mineralized rock will be sent to a commercial analytical laboratory or assay office for assay. Obviously, knowledge about the geological nature of gold deposits and particularly of the rocks and deposits in the area of interest will aid the prospector.

    Thank you for this valuable information and Good job J.R.

    Regards miners

  16. Thank you for the salient info my friend.

  17. My land is red claw with quartz rocks of various sizes in the clay and on top of the ground.
    These quartz rocks look like what you show in that photo. Could there be any gold in them?
    Richland County NE of Columbia SC

  18. If you're located in the gold mineralization area of NC there's a possibility...

  19. High J.R. I'm Moving to Lebanon, Oregon. Could you point me in the right direction where I should start looking. I enjoy recreational metal detecting and I'm not familiar with this area. Are there any specific types of host rocks to look out for in this area. To the east are the Three Sisters near Bend but to the West I'm in the dark all the way to the coast. Sure could use a little help. Thanks Barry

  20. Barry I'd love to help you but my experience in Oregon is virtually non-existent. I'd suggest getting in touch with a local prospecting club. Sorry!

  21. Can I use a hammer and chisel to extract quartz vein in bedrock with gold detected from my metal detector?

  22. Probably the only way to get it out I would imagine.

  23. I have a lot of quartz on my land in central Wisconsin, white, rose, orange etc. does that mean anything? Rumor has it that someone had a gold claim long ago somewhere in this vicinity.

    1. I live in Western WI along the banks of the Mississippi. I would not be surprised if there were gold near the areas where ancient river beds once branched off. On the bedrock map you can see the ancient river valleys.

      Just digging in my back yard where there is a valley I've pulled up all types of rocks I'd never dug up anywhere else. Including quartz. The ground is clay and heavy iron and or copper.

    2. Always worth checking out Jack.

  24. It just means you have quartz on your property unless any of that quartz is mineralized (iron stained or shows the presence gold, iron oxides or sulfides).