History & Geology
Epithermal Gold and Silver Deposits
April 2017 by Chris Ralph
Epithermal 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.
Prospecting for Pegmatites
…in some cases pegmatites have produced individual mineral crystals that are enormous, attaining lengths of over 40 feet long, and many of the world’s largest mineral crystals are examples that were found within pegmatite deposits.The Goldfield Mining District -- Then and Now
In 1983, some of the ore yielded more than 2,500 ounces of gold within 30 feet of the surface. The shoot pinched to a narrow vein.
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.
Gangue Minerals - What Do They Tell Us?
There are a large number of different kinds of gangue minerals, and each of them has its own tale to contribute to the story of the chemistry and geology of a deposit.
All About Garnets
I get a lot of questions from prospectors about garnets, their value and what they tell us about the geology of some types of mineral deposits. So I thought it would be a good idea to take a closer look at the lowly garnet and learn a bit more about it.
Sierra County Gold—Part II
...we will continue our examination of the rich streams and mining districts, and then take a look at some of the big nuggets that have been found here.
The Rush to Treasure Hill
There were some exceptional times in the far-flung history of the West. Rich finds of minerals that set men’s souls ablaze. From the rich gold fields of California, men who arrived too late to find riches went searching in every direction. The trail that we will follow leads east, past the shining silver district of the Comstock Lode.
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• 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
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