History & Geology
Ask The Experts
June 2015 by Chris Ralph
Sulfides and oxides—what's the difference between the two?Critical Minerals: Tungsten
Because tungsten minerals are heavy, exploration can be done using stream sediment samples. Prospectors looking for gold have found scheelite or wolframite in their placer concentrates, and in some cases this has led them to make important tungsten finds.
Enrichment of Mineral Deposits by Weathering—Part II
While both zinc and lead deposits also are enriched by the surface weathering process, in part two we will look at the enrichment process for copper and also gold deposits, and at the interpretation of leached outcrops to figure how rich the concentrated deposits below them may be.
The Downieville Gold District
Many locals are just waiting for California to allow dredging once more, especially with the current gold prices. There are still plenty of good opportunities for prospectors in this area, just as it has been for so many years.
Researching Mineralized Areas
There are a load of ways to do research, and I’m going to talk about how I do it—maybe you’ll get some ideas that will work for you, too.
Gold, Quartz & Chalcedony—Part II
The specific gravity of chalcedony is 2.58 to 2.64. This is slightly lower than coarsely crystalline quartz because of slight porosity in chalcedony. Being so light, it will easily wash out of a gold pan.
The Heavy Minerals in Your Concentrates
The fact that mineral deposits can contribute specific types of heavy minerals is why the analysis of the heavy mineral concentrates in the streams of an area can be an important prospecting technique for finding undiscovered mineral deposits.
Ask The Experts
Sulfides and oxides—what's the difference between the two?
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