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.
Amy's Exploration of NC Geology 