Ray Mica Mine Big Beryl & More

Ray Mica Mine
The Big Beryl & More
Yancey County, North Carolina
February 2008
By Mike Streeter
(mcstreeter@charter.net)

It was an hour before dawn broke and we were already making our way up to the Ray Mica Mine spoil piles. Without our head lamps to cut through the absolute darkness, we would have barely been able to see our hands in front of our faces. As we made our way up the rocky trail's moderate incline, the only sounds that we could hear were from our heavy breathing, the crunching from hiking on loose stones and an occasional snap from stepping on a fallen tree branch.

"Hey, you alright back there", I called out to Chrissy who had fallen back.

"Yep, I'm coming!", her voice rang out from a distant spot of light in the darkness.

"See that you do!", I retorted, using one of my many trademark wisecrack remarks.

While it may have seemed to some that it was way too early to be rockhounding, our plan for the day began with an activity that required darkness. But, before I get to this and the rest of the story, let me first introduce you to the Ray.

The Ray Mica Mine is actually a series of cuts, shafts and stopes that extend in a granite pegmatite approximately 1,200 feet along a northwest to southeast strike. Garrett Ray first worked the mine for mica in 1869. In those early days, mica was used as windows for houses and heaters. Muscovite is still used today as insulating material in electrical equipment, in paints to increase weatherability and to reduce running, in the manufacture of wallpapers to give them a silky or shiny luster, in the manufacture of lubricants and in dry-powder fire extinguishers. The Ray mine was closed and reopened many times throughout the years until the Wray mining company abandoned it as unprofitable in May 1944 after the U.S. Geological Survey mapped the mine as part of the Strategic Minerals Investigation Program. What remain today in the heavily forested area of Yancey County are extensive spoil piles that extend down a steep slope from the crest of a divide to an unnamed creek that flows over and under jagged pegmatite rocks.

The geologic history of the Ray Mine pegmatite has been traced back to about 390 million years ago when the last major mountain building events (orogenies) to affect the southern Appalachians began. The Acadian orogeny and subsequent Alleghenian orogeny took place when the African tectonic plate collided with the North America plate. The energy from this collision, that would eventually form a super continent called Pangaea, was so great the Appalachian Mountains were folded and thrust up to an elevation greater than the present day Himalayas.

Sometime between 390 to 320 million years ago, a feldspar-rich igneous body called alaskite intruded pre-existing metamorphic rocks. Alaskite is a local term that refers to a medium to coarse-grained, light colored, non-foliated to weakly foliated, massive igneous rock composed of oligoclase feldspar, quartz, microcline feldspar and muscovite mica and other minor accessory minerals. Slow cooling and/or high pressures exerted on magma derived from the alaskite bodies allowed crystallization of unusually large and exotic minerals forming pegmatite dikes, including the Ray Mine pegmatite. The major minerals making up the Ray Mine pegmatite include plagioclase (albite-oligoclase), muscovite, microcline and quartz. Accessory minerals include almandine garnet, apatite, beryl, biotite, ferrocolumbite, goethite, amazonite, and schorl. There are numerous trace minerals that include autunite, thulite, elbaite, ferberite, ferrotapiolite, fluorite, kyanite, lepidolite, microcline, molybdenite, monazite, hyalite, pollucite,pyrite, rutile, spessartine, sphalerite, tobernite, and zircon.

By about 300 million years ago, the Alleghenian orogeny peaked and heat and pressure from it caused even more metamorphism to occur to pre-existing rocks. The Ray Mine pegmatite trends southwest to northeast, just like the overall structural pattern of the southern Appalachians.

Tectonic forces in the past 250 million years have been relatively passive as compared to earlier great mountain building events. As plates reversed directions, Pangea began to stretch apart about 225 million years ago. In the southern Appalachians, this final period is marked by continued regional uplift accompanied by extensive subaerial erosion.

The Ray mine is arguably the best place in North Carolina to find facet-grade aquamarine, a greenish-blue gem variety of beryl. The largest beryl crystals are reported to be about 4 inches in diameter and 5 to 6 inches long, although facet-grade crystals of this size are extremely rare. I've heard tales about much larger crystals, but have yet to see one of these myself. The cuts, shafts and stopes are not accessible and should be avoided. All collecting must be done in the spoil piles that extend along a steep slope to beyond the creek that flows through the area. To find minerals, you can dig up and screen spoil pile materials in the creek or simply dig into the slope or creek area while keeping a sharp eye out for minerals as you do. Many collectors find crystals by breaking larger rocks. Mica, feldspar and tourmaline are plentiful but the other minerals, including beryl, are more difficult to find.

So, what would prompt us hike into the National Forest in the dark? The answer to this question can be summed up in a single word: fluorescence. Several Ray Mine minerals fluoresce under shortwave ultraviolet light, including apatite (pale yellow), hyalite opal (bright green) and fluorite var. chlorophane (pale bluish purple). We thought that it would be a hoot to bring along our ultraviolet lamp to light up and locate these minerals, but this had to be done in the dark.

After setting up our gear where we had planned to work during daylight hours, we carefully made our way up and down the spoil piles along the creek with the shortwave lamp. This wasn't easy in the dark, but we stayed low, felt our way along and turned on our head lamps when necessary. Within half an hour or so, dawn started to break and there was just enough light for us to better see where we were stepping. We discovered lots of apatite and some hyalite opal in matrix before there was too much daylight to continue. The following pictures illustrate some of what we found before sunrise.

After finishing our nocturnal adventure, we started digging. It is generally my practice, no matter what part of the extensive spoil piles, to dig down to

a layer of rock that has not seen the light of day since it was dumped by the miners. It is intuitively obvious that there is more chance of finding goodies in rocks that have gone untouched by other rockhounds. However, getting down to the proper depth can be extremely challenging for several reasons: 1) the spoil piles can be up 10 feet deep; 2) less experienced or physically unable rockhounds have pushed rock and debris down slope burying the untouched rock even deeper; and 3) there are many large boulders at depth that have to be busted up in place just to move.

The digging itself is pretty basic pick and shovel work that requires no explanation - other than to say that it is BRUTAL. However, there are different techniques to find beryl and other minerals. Some rockhounds will screen all the finer grained material that they dig up to find loose crystals. This is done either in water obtained from the nearby creek or in the creek itself. As I mentioned above, my method of choice involves digging down to the untouched rock where there is little to no finer grained material. It has been my experience that the very best layer is where the rocks and boulders look as though they had been dumped by miners, washed by rain and then buried beneath more rocks many decades ago. The best beryl in matrix specimens that I have found were recovered in rocks that required no washing to see the crystals. However, the untouched rock layers are not always free of finer material, including dirt, that sticks to the rocks, thus masking the minerals. In this case, each pegmatite rock recovered must be washed in water to remove the dirt. Chrissy and I work as a team whereby I dig 'em up and she washes 'em in a bucket of stream water. I will periodically stop digging to bust apart all the larger rocks and boulders and will sometimes find good stuff hiding inside. I will also carefully cob the rocks that are showing beryl and other minerals. Proper cobbing, so as to not destroy a specimen, takes experience, patience, nerve and a bit of luck. Some suggest that it would be better to take a rock home to employ some sort of hydraulic rock splitter for cobbing, but the size of the boulders and the 1/2-mile hike back to the truck makes this an undesirable option for me. Knowing when to stop cobbing so that you don't ruin a specimen also takes experience along with discipline. No doubt, I have ruined many a specimen by giving it one too many whacks in an attempt to make it "perfect". But, the way I figure it, you have to lose a few to get a few and I prefer to do my losing in the field. Sometimes luck is squarely on our side, as was case this day.

Early afternoon, I pulled out a 30-pound boulder that contained what appeared to be two large beryl crystals barely showing on one side. I didn't take a picture of it at the time, but for illustration purposes, I used a photo editor to recreate its approximate appearance (see picture to left). As I often do, I put the rock aside to cob later. I have learned that it can be better to let the adrenaline rush from finding a potential good specimen subside before attacking it with a hammer.

After about an hour, I decided it was time to cob. I began hammering the boulder as far away from beryl as possible. I used the feldspar's cleavage to my best advantage to slowly remove waste rock and hopefully uncover the crystals. Exploiting cleavage and a pegmatite's natural fractures and other weaknesses without ruining a specimen by either knocking out or shattering beryl crystals is almost an art that one day I hope to master. Somehow, with carefully-directed blows, I managed to uncover enough of the beryl to realize that it was actually a single crystal, instead of two as I had previously thought. Yowzer! The smaller end of the crystal was almost fully exposed, but the bottom wider end was still mostly covered with rock. Again, I used a photo editor to recreate the approximate appearance of the specimen at this point (see picture to right). It was a nice specimen just as it was and I decided to not push my luck by whacking on it any more . . . at least until I changed my mind a half hour later (welcome to my compulsive world).

With Chrissy seeming to wince and sometimes look away with each hammer swing, I attempted to remove just a bit more matrix and expose more of the fat side of the beryl crystal. Just about the time that I thought that the rock would never cooperate and I would be forced to give up and be satisfied with what I had, a small crack emerged on its surface. "Uh, oh", I said, much to Chrissy's chagrin. "Now I've done it", thinking that I had messed up another one. Not really knowing exactly what would happen and fearing the worst, I slipped a thin chisel blade into the crack and pried it apart. "Oh, my God!", I exclaimed as I held up and turned over the top portion of the boulder with the entire beryl crystal perfectly attached, intact and greatly exposed. The rock could not have broken off any better, and we ended up with a relatively thin plate that contained the big beryl, a small side beryl and splashes of shiny black tourmaline. I could hardly believe my luck as I had no idea whatsoever that the rock was going to break the way it did. The real-life final specimen is pictured below.