North Carolina Beryl

North Carolina’s beryl is amazing. Yes, I’m starting out this blog with a blanket statement. Yes, I’m ok with that. Many gemstones come from the mineral material which has the most desirable aesthetic qualities such as size and clarity.

The beryl family of minerals (with its gemstones!) is named for beryllium aluminum silicate Be₃Al₂Si₆O₁₈. The silicates are the most abundant class of rock-forming minerals. Specifically, beryl is considered a cyclosilicate because it has a 6-link ring of linked tetrahedra. Ore-grade beryl is used with the manufacture of alloys once the beryllium is extracted. Gem-grade beryl is faceted or cut en cabochon in order to be used for jewelry.

Green beryl is known as emerald. The green color of emerald is due to chromium.

Light blue or greenish blue beryl is known as aquamarine. The light blue color of aquamarine is due to Fe²⁺ ions.

There are more colors within the beryl family such as white, colorless, red, yellow (heliodor-colored because of Fe³⁺ ions), and pink (morganite-colored because of manganese). These gemstones have a hardness of 7.5-8, thereby making them very suitable to be worn in jewelry. North Carolina’s beryl is most often found in pegmatites which are igneous intrusions with a lot of quartz, mica, and feldspar. Generally, almost all beryl is found in these pegmatites. Here’s the easy way to think about it: a pegmatite is granite. Quartz (silicon dioxide SiO₂) is easy to spot because it is one of the most common minerals on earth. Quartz forms hexagonal crystals which are characterized by having ends in double rhombohedrons. Mica is also easily characterized by its structure. It is a sheet silicate which easily flakes off similar to peeling sunburn. Feldspar is also a very common mineral (it makes up roughly 60% of the earth’s crust), but it may not be as easy to recognize compared to quartz. The hexagonal crystals of the beryl family are the best to look out for when searching for gemstones in North Carolina pegmatites. Anyone searching for beryl in North Carolina should first look for areas with pegmatites. It is much easier to find what an emerald or an aquamarine should be found in, trust me.

Hiddenite, North Carolina is home to the Emerald Hollow Mine. This is the only mine in the United States which is open to the public. I have not been here before and am therefore unable to say about whether it is worth the effort, but I definitely plan on visiting this mine sometime in the future. North Carolina is an amazing place to find gemstones, but I am wary of going to mines which charge admission and everything like that because many mines are “salted” with gemstones in order to keep people coming back year after year. It is simple enough to search online about which mines have been “salted” with gemstones. They are often really cheap gemstones bought overseas and either put into buckets or dumped in streams for the public to search through and hopefully find some fun minerals which can be faceted into gemstones.

John Rock and Looking Glass Rock

Overlooking Looking Glass Rock from the rock face of nearby John Rock

I went on a hike with some friends to the summit of John Rock in the Pisgah National Forest yesterday afternoon.  There was a winter storm in North Carolina the previous day, but the temperature got up to 47 °F which was warm enough to make almost everything melt by the time we started hiking near 1:00 PM.  The nearby Davidson River was swollen with the new snowmelt.

Geologically speaking, Looking Glass Rock is a pluton.  A pluton is a big ball of granite which would have become a volcano if it had not cooled before reaching the surface.  Volcanoes occur when at convergent boundaries when crust subducts and melts underneath the surface.  This melting crust forms magma (the same thing as lava, but lava occurs above the surface whereas magma occurs underneath the surface) which is less dense than its surroundings and rises toward the surface.  What are now the North American and African Plates used to be much closer together and were actually at a convergent boundary.  This convergent boundary formed the Appalachian Mountains when the oceanic portion of the plate subducted.  This continental collision formed the Appalachian Mountains which still exist from Alabama northeast up to Maine in the eastern United States.  We were so excited to view Looking Glass Rock from John Rock because the name “Looking Glass” is comes from how ice appears similar to a mirror when the sun reflects on it.  The warmer temperatures and exposure to sunlight actually made Looking Glass Rock not reflective, but John Rock’s pluton was mostly shaded and still covered in a layer of ice.

I am the biggest fan of hiking and geology in my group of friends by far, so I chose the hiking location and plan for the day.  Basically, they told me they would be up for going wherever I wanted to go.  The Pisgah National Forest is one of my favorite places for hiking because it is such a large area which is well maintained and protected.  My interest in John Rock and Looking Glass Rock came because of a lesson in class we had about the history of the Appalachian Mountains.  I wanted to know if I could see any of these ancient volcanoes which occurred because of the convergent boundary which originally formed these mountains.  Looking Glass Rock and John Rock would have been volcanoes, but the magma in both of these areas cooled too quickly before forming into volcanoes.  The Appalachian Mountains were once connected to the African continent, but later broke apart and moved away based on the hypothesis of continental drift.  The dominant force in this area is erosion, but many think that the Appalachian Mountains were once as high as the Rockies.  Veins of quartz were seen in the granite as well as seen along the trail itself.

Many mountain peaks I have hiked to in North Carolina feature granite outcrops, so I find these areas to be particularly interesting and beautiful.  Beacon Heights and Rough Ridge are two favorites.

A view of the mountains taken from the rock face of John Rock

Mountain laurel and rhododendron were everywhere along the trail and even right beside the rock face

Want to go?  Want more information?
http://www.blueridgeheritage.com/attractions-destinations/looking-glass-rock

Enjoying Geology while Hiking

I like to head to the Blue Ridge Parkway roughly about once a month to do some serious hiking. My major deciding factor on which trail I want to hike is simple. I want to see views.

http://www.blueridgeparkway.org/v.php?pg=61 is a link from the Blue Ridge Parkway’s website of the hiking trails within North Carolina according to overlooks and mile markers. Most of the trails are listed, but somehow there are a few trails missing. Anyone who sees this list may wonder about the trail names and what they mean. I know I did. My goal with this first entry is to give a rough explanation, geologically speaking, about what some of the features in the trial names mean. Balds and knobs are just two examples of features I had never known about before I actually was first able to experience them and see them in real life. How would I describe these features to other people though? These definitions are how I would describe these features and are not completely accurate, so I hope that anyone who reads this can offer some more insight by leaving a comment. My assumption is that these features are probably found in mountain ranges of different areas, but maybe these particular terms are of some sort of southern Appalachian vernacular.

A bald is a summit or crest of a mountain which is covered by native grasses or lowlying shrubs rather than covered by a heavy forest. I was told by a hiker before that a bald occurs in the southern Appalachian Mountains because of the unique climate which has too short of a growing season for forests. So does this mean that a “bald” only occurs in this area? Maybe. This strange occurrence is unique because a bald occurs with a warm climate and high elevation, and these factors are often very suitable for forest growth.

A knob is a hill or mountain with a rounded top. A rock climbing buddy once told me that knobs are fun for bouldering. An important feature of a knob is that it does not have much or any plant cover.

A pinnacle occurs at the top of a mountain where there is a sharp peak. The first pinnacle I ever hiked to the top of was actually part of Crowders Mountain in Gaston County, North Carolina. It is about 45 minutes or an hour from where I live, so it is somewhere I enjoy hiking frequently.

A gap is an area along a mountain ridge which is lower than the surrounding areas. Windy Gap is an area which comes to mind whenever I think of a gap because it is an area I traveled to frequently as a child. Maybe its name is “windy” because this lowlying area acts sort of like a wind funnel?

I may not have defined these terms correctly or in a manner which is the least bit helpful, but the whole purpose of science is the pursuit of new knowledge. I will be the first one to ask questions because I know I do not have all the answers. Keep exploring.

And Wikipedia has a great list of balds at http://en.wikipedia.org/wiki/Appalachian_balds for anyone interested