Rockhounding USA
: an informative and media-rich blog with articles, photos, videos, and maps to a wide variety of rock, mineral, fossil, and Indian artifact collecting sites across the USA.

Thursday, February 8, 2018

Mineral Minute - Episode 3: Tourmaline

Today's mineral: Tourmaline

Tourmaline is a huge family of boron silicates that share crystal structure, but vary in chemical composition. It has a hardness of 7- 7.5 , cleavage is indistinct, a white streak, and a glassy luster. Tourmaline is known to be virtually any color. This awesome gem can even be multi-colored, such as watermelon tourmaline, which was was first discovered in 1902 at Dunton Quarry in Oxford County, Maine. The pegmatites of Maine still provide a rich source of this most sought after variety. 

Tourmaline can be found in the U.S., Afghanistan, Pakistan, Russia, Myanmar, Sri Lanka, Africa, and Brazil. Here in the United States, tourmaline can be collected at the:

Himalaya Mine at Lake Henshaw, California
Oceanview Mine in San Diego County, California
Hogg Mine near LaGrange, Georgia
Harvard Quarry, Oxford County, Maine
Brushy Creek Mine near Asheville, North Carolina
Mt. MIca in Paris Maine
And finally Mt. Apatite, near Auburn, Maine.

Sunday, January 28, 2018

Amazing Tales of Geology - Episode 3: The Giant Crystal Cavern of Naica, Mexico

We’ve all seen crystals small enough to hold in your hand, but how about crystals big enough on which to stand?

That’s exactly what happened to a pair brothers as they were drilling hundreds of meters underground in a mine near Naica, Mexico in the spring of 2000. Eloy and Javier Delgado discovered a horseshoe-shaped cavity in the limestone, and once they had pumped out the water, the two were met with a fantastic wonderland containing the largest forest of free-standing crystals known to exist in the entire world.

It may have looked like a Hollywood movie set portraying an alien planet, but it was right here on Earth, a natural formation almost a thousand feet below ground. News of the phenomenal geological treasure spread rapidly, and scientists literally descended on the unbelievable site, dubbing it the Cave of the Crystals or the Giant Crystal Cave, and with good reason. The enormous structures are composed entirely of translucent Gypsum (Selenite), with the largest crystal measuring in at nearly 40 feet long, weighing an estimated 55 tons.

Conditions in the cave were brutal, with temperatures hovering around 136 degrees and humidity reaching 99%. Even wearing specialized suits, researchers could only remain in the cavern for around 30 minutes at a time. Unfortunately, any samples of the crystals from this specialized environment would quickly deteriorate if brought up to the surface.

Interested in the prospect of visiting the Giant Crystal Cave one day? Don’t get too excited, the mining company ceased pumping operations in February of 2017, and the cavern is once again flooded with hot, mineral rich water. But don’t worry, even if you can’t be there in person, there are a few excellent documentaries available about this geological masterpiece.

It’s the Giant Crystal Cave in Naica, Mexico, another Amazing Tale of Geology brought to you by Rockhounding USA. Check out our other videos in this and other series.

Saturday, January 27, 2018

Amazing Tales of Geology - Episode 2: The Black Star of Queensland

Could it be true that one of the most valuable and beautiful gems in all of human history was once considered a worthless rock and used as a simple doorstop in Australia? The shocking answer is YES. Watch this short video about the amazing history of The Black Star of Queensland:
In 1938, an excited 12-yr-old boy found a palm-sized, dark rock on a hillside in Queensland, Australia. Little Roy proudly showed the stone to his family, but his father, Harry, was so unimpressed that he used it as a doorstop in the back of their tiny shack. But Harry Spencer, (himself a miner in the central Queensland gem fields), should have known better. The rejected rock sat on his dusty floor, forgotten for almost ten years.

But then, Harry learned that sapphires could be almost any color. He finally realized that the stone that his son had found was likely a black sapphire, and quickly put out the word that he had a valuable gemstone for sale. The news of this find garnered the attention of the famous jeweler Harry Kazanjian, who journeyed from southern California in 1947 to Queensland to purchase the one-of-a-kind treasure. Kazanjian paid the Spencer family $18,000 for the gem, which translates to approximately $200,000 in today’s dollars.

Kazanjian spent nearly two months studying the enormous stone, planning his cuts and facets with the hopes of revealing the highly-prized asterism that might be hiding deep within. His patience and planning paid off handsomely, and after removing over 400 carats of surrounding material, a six-pointed star appeared in the center of the 733-carat masterpiece.

Dubbed “The Black Star of Queensland,” the spectacular gemstone was appraised as being worth over $1 million dollars in 1949. Now surrounded by a ring of 35 diamonds, the Black Star of Queensland is currently valued at close to $100 million dollars and sits in the private collection of an anonymous European gem collector. From worthless doorstop to priceless treasure, now you know the amazing tale of the Black Star of Queensland.

Mineral Minute - Episode 2: Amazonite

Watch our latest episode of Mineral Minute for a quick look at Amazonite, that bluish-green to rich green variety of the feldspar family (most famously found around the Pikes Peak, Colorado area)


Today's mineral: Amazonite.

Amazonite is a pale greenish-blue to deep blue-green variety of microcline Feldspar. Amazonite has a hardness of 6-6.5, cleavage is perfect in one direction and good in a another, a white streak, and a glassy luster. The origin of this mineral's color is debated, but it has been attributed to lead and water in the crystal lattice.

It is probably named after the Amazon River, even though large deposits have never been found near there. Amazonite is commonly found as large crystals with white streaks and is often associated with smoky quartz, especially in the U.S.

There are large deposits in Russia, Burma, India, Ethiopia, Madagascar, Brazil, and the United States. Here in the U.S., Amazonite can be collected at the: Morefield and Rutherford mines in Amelia county, Virginia. Along Gold Camp Road, near Colorado Springs, Colorado. At Crystal Park, near Manitou Springs, Colorado. Along Barr Trail, on Pikes Peak, Colorado. And in Devils Head, south of Denver, Colorado.

Here is a paper which seeks to confirm that it is LEAD that is responsible for the bluish-green hue of Amazonite: http://www.minsocam.org/ammin/AM70/AM...

Saturday, January 20, 2018

Mineral Minute - Episode 1: Amethyst

Watch this short video as we spend 60-seconds exploring everyone's favorite purple variety of quartz: Amethyst, right here on Mineral Minute:
Today’s Mineral: Amethyst

Amethyst is a colorful variety of the quartz family, often noted for its pale to deep shades of purple. Amethyst has a hardness of 7, no cleavage, a white streak, and a glassy luster. The famous hue of this mineral is caused by trace amounts of iron that are trapped inside the quartz lattice.

This iron is then further modified through different levels of radiation deep within the earth, producing a wide range of colors from reds to deep purple.

Amethyst is often found as large crystals, or in clusters, or within geodes at many famous deposits in Brazil, Uruguay, Mexico, Russia, Canada, and South Africa. Here in the United States, Amethyst can be collected at the: Emerald Hollow Mine in Hiddenite, North Carolina Diamond Hill Mine near Abbeville, South Carolina Amethyst Queen Mine near Nancy Hanks Gulch, Colorado Amos Cunningham Farm near Due West, South Carolina. and Jackson’s Crossroads Amethyst Mine near Jackson Crossroads, Georgia.

Note: All of these locations require permission and most require a fee for collecting.

Fossil Shark Teeth at the WM Browning Cretaceous Park

If you visit most creeks in the southeast you are likely to find frogs, lizards, or even an occasional snake. But...SHARK'S TEETH? In this video episode, we travel to Frankstown, Mississippi in search of the remains of some of the best killers ever to swim the seas:


Amazing Tales of Geology - Episode 1: The Million Dollar Pocket

Aquamarine.

That beautiful pale blue to bluish-green member of the Beryl family, treasured by gem cutters and prized by mineral prospectors worldwide. What rockhound wouldn’t be thrilled beyond description to crack into a gaping pocket laced with dozens of long, unbroken, gem-quality aquamarine crystals still lodged perfectly atop a gorgeous matrix?

In the fall of 2004, that once-in-lifetime-thrill came to amateur prospector Steve Brancato, as he searched for topaz on the chilly, steep slopes of Mount Antero, the 10th highest peak in the state of Colorado. The high-school dropout turned fulltime gem hunter first extracted a loose 25-carat aquamarine, and that blue crystal became the first of many, many more over the course of the next few days. Brancato had uncovered the largest and most valuable pocket of aquamarine crystals ever unearthed in the United States. Once extracted and restored, the impressive slab measured roughly 3 feet by 2 feet, and was encrusted with dozens of aquamarine crystals rising alongside a forest of gorgeous smoky quartz points.

In a touching move in honor of his mother, Steve Brancato dubbed his incredible discovery “Diane’s Pocket.” As the biggest aquamarine cache ever found in the USA, its value is difficult to appraise, but some experts have estimated this one-of-a-kind wonder to be worth well over a million dollars.

“Diane’s Pocket” was first displayed publicly at the Tucson Gem and Mineral show in February of 2005, before being acquired by Bruce Oreck, a trustee of the Denver Museum of Nature and Science. Oreck then donated his spectacular purchase to the museum, where it has since been on continuous display for all the world to enjoy. The incredible, million-dollar discovery of Diane’s Pocket, another Amazing Tale of Geology brought to you by Rockhounding USA.