History & Geology
Exploring Iron Oxide Copper Gold Deposits
November 2017 by Chris Ralph
The excitement over IOCG deposits began with the discovery of a monster deposit at Olympic Dam in Australia in 1976. The discovery was accidental as the operator was searching for strata-bound copper deposits.
How to Recognize Hard Rock Gold Ores
I regularly get inquiries along the line of: “Hey, I found this rock, and I think it might be gold ore. How can I tell?” Prospectors are always on the lookout for gold-bearing rocks that may be the source of any nearby placer gold.
What Are Those Rocks In My Pan?
The placer mineral identification key is designed to answer this question. It attempts to recognize all the minerals in your gold pan concentrates.
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.
Placer Gold Deposits of Utah
The placer deposits of Utah occur in two distinct types of environments. These are 1) placers found adjacent to, and derived from, gold, silver and base-metal deposits; and 2) placers found in major rivers and derived from unknown, distant sources.
California: The Land of Big Nuggets—Part I
The nugget sat there in plain sight, though it was covered in dirt, while hundreds of people had passed that way every day.
Understanding Large Gold Deposit Types: Discovering New Mines
The other opportunity that I see is in seeking unusual types of deposits. Specifically, the prospector would be searching for the stuff no one (or almost no one) is searching for. These deposits are effectively hiding in plain view.
Green Valley Gold District, Payson, Arizona
Most gold-bearing quartz veins found in the district were fracture fillings in faults enclosed by crushed quartz zones along their margins. Since the host rocks were often extensively weathered, portions of the veins stood out as positive, resistant outcrops. The gold-bearing veins ranged from a few inches wide to the vein at the Gowan mine that was as much as 12 feet wide.
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Over the Divide: Nancy Glenn; Sondra (Adelson) Bernzweig
