Epithermal Gold and Silver Deposits
April 2017 by Chris RalphEpithermal deposits form in the ground at shallow depths. They are popular with prospectors because can yield very rich deposits and they are widespread in the Western US.
Kimberlite is very difficult for geologists to find, let alone prospectors and rock hounds. This is because kimberlite is rarely exposed on the surface and few people know how to identify the rock.
The majority of the gold produced in Goldfield has come from ores that are close enough to the surface to be oxidized by the air. This oxidized ore is normally a soft, shattered, earthy material usually stained yellow to brown by oxides of iron.
From time to time I’ve been doing a series on critical metals and how important they are to our complex and technological society. This month we are going to take a look at copper, and how important that metal is to our modern lives.
Some of the wire forms are strange and fantastic, with wires sticking out in twisted, seemingly random directions. Others have deformed crystals and all of them have significant value to collectors.
Chances are better that both types of gold did not come from the same source. Let's look at the probable conditions to cause two types of gold in a placer.
Because quartz and gold may be deposited together across a considerable range of temperatures, not all quartz veins are the same, and there are several different types of gold-quartz deposits.
If developed with metal detecting in mind, this virgin ground could be a bonanza for nugget hunting.
The Bawl Mill • Legislative and Regulatory Update • Ask The Experts: Is an XRF gun useful for prospecting and mineral identification? • Ask The Experts: Is this deposit worth working? • Ask The Experts: Can a long range locator probe detect gold in quartz? • Weathering, Erosion and Placers • The PIGMI—a DIY Crevice Tool • Diary of a Diamond Prospector • The Ups and Downs of Nugget Hunting • Melman on Gold & Silver • Mining Stock Quotes and Mineral & Metal Prices