History & Geology
Calcite and Limestone
February 2017 by Chris Ralph
The other distinguishing feature of calcite has to do with its chemistry. Geologists sometimes take a small bottle of dilute hydrochloric acid out into the field with them because calcite reacts with acids to make a bubbly foam.
The Golden Days of Julian, California
Some scattered reports say that gold may have been washed from streams here as early as the 1840s, but the undisputed major discovery came in 1870.
Testing Ores for Free Gold
I get a number of questions from people about testing and treating hard rock ores. The simplest way, but also an expensive one, is to just have an assay test done by an independent assay firm. As an alternative...
All About Chalcopyrite
…there are loads of different copper minerals, but a large number of them form first in the ground as chalcopyrite and then through the effects of weathering are changed into other minerals like malachite, cuprite and chrysocolla.
The Ups and Downs of Geologic Faults
Faults are fractures, breaks and broken zones in the Earth’s crust where one side of the break has moved relative to the other, and they come in many different varieties.
Eastern Arizona: Gold and Base Metal Deposits—Part I
Arizona is well-known for its copper-gold porphyries and massive base metal-gold sulfide deposits such that primary gold deposits in the state are often overshadowed.
Ophir—Possibly the Best Kept Secret in Alaska!
...I decided to excavate the semi-frozen high-bank that was resting on a soft shale bedrock footing. Within three feet, I encountered an intrusive!
Third Largest Nugget in Existence Returns to Dallas
While the bullion value of the nugget is already substantial, the size and rarity of the Ausrox Nugget combine to make its worth invaluable in the collector market.
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