NC Geology facts and factoids: Gold and hiddenite
Every now and then I get tired of answering the same questions over and over again, so I write something to treat that question in detail. Then when I get the question, I direct the questioners to the article, roll over and go back to sleep.
The first article addressed the question of The First Gold Rush in North America: North Carolina or Georgia? Looking into the question in detail yields some interesting results.
Schoolkids in North Carolina are taught the story of Conrad Reed, skipping church to shoot fish in the creek, and finding a huge gold nugget instead. That was in 1799. Gold was first discovered in Guilford County, North Carolina, and sent to Governor Josiah Martin in 1774. Gold was later found in Virginia in 1787, as recorded by Thomas Jefferson himself. The reality is that “gold fever” spread exactly like a disease, starting at the Reed property in 1799 (now Reed Gold Mine State Historic Site, well worth the visit), then to the neighboring farms, then to that region of North Carolina. These weren’t really gold rushes, they were just the development of a new money-maker in the communities. In 1828, the Brindletown Gold Rush started in Burke County, North Carolina. Winter of 1829-1830 saw the spread of the fever throughout the Southeast with the start of the Dahlonega Gold Rush in Georgia. In 1849 gold was discovered in California and the gold fever was a nationwide phenom. Historically, it grew exponentially like any other disease, with isolated cases in 1774, 1787, and 1799.
The second article dealt with the question “Is the mineral hiddenite found only in North Carolina?” On a regular basis, somebody in a gem and mineral club will get into an argument with someone else about that question. I would get the call to arbitrate the disagreement.
I set the second question against the backdrop of mineral nomenclature and 19th Century amateur mineralogists behaving like children. Mineral nomenclature can be a real snooze, but in this case, it’s important because there is no internationally and scientifically recognized mineral species named hiddenite. There are formal and detailed means of naming minerals, intimately tied to the science of mineralogy, all under the oversight of the International Mineralogical Association (IMA). By these standards, the formal name should be “chromium-bearing spodumene,” the chromium being the source of the anomalous green color. Hiddenite is a historical leftover, a gemstone name, and there really isn’t anyone in charge of names of gemstones. In reality, every few years a new gemstone name will crop up as part of some marketing campaign. Mineral names are science, gemstone names are marketing.
Back to the question about hiddenite. Some people insist that only a gem-quality spodumene that is green due to chromium can be called a hiddenite, so hiddenite is only found in North Carolina. This isn’t true. A search of the scientific literature revealed sites from Siberia, India and Brazil. There are actually more reported sites, but I only list the ones where they published their chromium data. One thing I didn’t go into in the article is that all of these discoveries come from pegmatite districts that also have emerald. An emerald is (often) a pegmatite mineral, a beryl that is green because it contains chromium. If beryllium pegmatites interact with a chromium-bearing wallrock to make emerald, then spodumene pegmatites can do the same to make hiddenite. Not only is hiddenite not limited to North Carolina, it’s reasonable to expect to find it in pegmatite districts that contain emerald.
Future geoblogs will deal questions such as
- Are the Appalachians (the Brushies, the Uwharries, etc.) the oldest mountains in the world?
- Is the New River the oldest (second oldest, etc.) in the world?
- Does North Carolina contain more minerals (more different minerals, more gemstones, etc.) than any other place in the world?
All of these are what I call “fake superlatives.” It’s the sort of thing seized upon to attract interest, without a lot in the way of fact checking. I’m really not interested in debunking these claims. The fun part is that each answer is more complex than expected, and illuminates a new facet of North Carolina geology, and illustrates the way that geologists work and think.