Blue Ridge Parkway The GARNETS of CRAGGY GARDENS EarthCache
Blue Ridge Parkway The GARNETS of CRAGGY GARDENS
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Difficulty:
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Size: 
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*NOTE* Especially IN WINTER CHECK TO SEE IF THE PARKWAY IS OPEN IN THIS AREA. IT IS CLOSED AT TIMES DUE TO WEATHER OR CONSTRUCTION!!)
(call 828-271-4779 or 828-298-2491 for information)
For those caching paperless, here is a shortened version of the logging requirements:
DO AT LEAST ONE of the following (or use the Photo option):
1) Describe the color(s) of the Garnets YOU can see embedded in the rocks at the coordinates.
2) Are the Garnet deposits that you can see at the coordinates well-formed crystals or not?
3) Is the rock at the coordinates Mica Schist or gneiss?
Note: While not required, A PHOTO (of YOU if you wish) at the cache location is always appreciated,
AND CAN BE USED IN PLACE OF YOUR ANSWER(S).
NOTE ADDED 3-24-11: WHILE THE CACHE AREA IS OPEN YEAR-ROUND AS LONG AS THE PARKWAY IS OPEN,(see the above note)
THE PIC-NIC AREA ROAD IS/MAY BE CLOSED TO VEHICLES BETWEEN around OCTOBER 31st & MAY 15th each year. If closed, you may park at the gate and WALK up the road (rating: Strenuous).
The pic-nic area road will re-open May 15th.
AS AN ALTERNATIVE to driving up to the cache,
Cachers may park at the Craggy Gardens Visitor's Center just up the road. At the LEFT END of the ROCK WALL is a TRAIL (rated Moderate - 1 mile one way) that goes up to the cache area. (This is a very nice trail)
There is a restored Historical Pic-nic Shelter halfway up.
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North of Asheville, North Carolina, the Blue Ridge Parkway passes through the Great Craggy Mountains, an area of exposed rock surfaces and high peaks that provides breathtaking views. Large expanses of native rhododendron cover the slopes and summits of the Craggies.
The Craggy Gardens area is located near milepost 364 along the Blue Ridge Parkway.
The unique beauty of this area is enhanced by the colorful geology found in the rocks here.
This area we are visiting today is known by local people as Craggy Gardens Picnic Area.
Starting mid-June, beautiful pink and purple blooms of Catawba Rhododendron → cover the Craggies. Throughout the summer, smaller native wildflowers cover the ground with vibrant splashes of color.
These natural gardens are "balds." A bald is a treeless area located on or near the summit of a predominantly forested mountain. Seen from a distance, the area appears bare. Closer inspection, however, reveals that balds are covered with low-growing vegetation - unique communities of plant life. Heath balds are predominately made up of woody shrubs such as rhododendron, mountain laurel, blueberries, huckleberries, flame azalea, and others which belong to the Ericaceae (heath) family. Grassy balds are made up primarily of grasses and wildflowers and, in some areas, they intermix with the heaths to form "pathways" through the rhododendron.
High, treeless summits such as these are unique to the Southern Appalachians.
What caused the balds? No one knows for sure. Some may have resulted from natural causes such as fire or dramatic climate change over long periods of time. Others may have been man-made. Certainly some were cleared, maintained or enlarged by early settlers.
We do know that many were used for pasturing livestock during summer months. In the Craggies, most grazing ceased in 1920, and all grazing was stopped in 1950 when the Blue Ridge Parkway acquired the land.
The grassy bald above the Craggy Picnic Area is currently being maintained through management by Blue Ridge Parkway resource management staff.
Now for some GEOLOGY
In the Late Proterozoic, about 700 million years ago, Earth forces tore the North American Continent apart. Huge blocks of crust were rifted from the mainland. Sediments from these crustal blocks washed into deep troughs that developed along the jagged edge of the continent. Underwater avalanches carried sediment far out into the ocean where they were interlayered with basalt and other volcanic rocks on the ocean floor.
These sediments composed of layers of gravel, sand, and silt, later hardened into rock and were metamorphosed to produce the rock unit geologists now call the Ashe Metamorphic Suite, This predominant rock unit consists of mainly an inter-layerd sequence of gneiss, schist, and amphibolite that formed on the ancient ocean floor over 600 million years ago. At many sites along the parkway in this area are good exposures of metagraywacke, gneiss, and mica schist right along and on either side of the road.
All of the rocks along this part of the Parkway belong to this unit. At spots where the rock has a banded, layered appearance, it is due to the alternating layers of the schist and metagraywacke.
Rocks of the Ashe Metamorphic Suite have been sculptured by millions of years of erosion into two prominent mountain ranges: the Black Mountains and the Great Craggies
Consisting primarily of hard, erosion-resistant metagraywacke, the Blacks are the tallest mountains east of the Mississippi, with six peaks rising to elevations of over 6,500 feet. The summits of the Great Craggies are almost bare of trees, covered instead with shrubs of the heath family as mentioned previously, from which they get the name "heath balds"(see above).
Craggy Gardens and Craggy Pinnacle, elevation 5,892 feet, display outcrops of mica schist and gneiss belonging to the Ashe Metamorphic Suite.
Some of the rock layers contain GARNETS. (see photographs )
Garnets are a very common and well-known mineral formed through metamorphic processes.
Garnets are, perhaps, best known as the birthstone for the month of January(incidentally, my birthstone).
The word garnet is derived from the Latin word granatus, meaning 'like a grain', which refers to the mode of occurrence wherein crystals resemble grains or seeds embedded in the matrix.
Garnets are very popular minerals for jewelry. They have a much higher hardness than fire opals or diopside, are much less expensive than emeralds or rubies, diopsides, and have a higher index of refraction than all of them. In fact, garnets have a higher index of refraction than all other commonly used colored gems. These factors combine to make garnets ideal for jewelry that is practical, economic, and beautiful. Industrial grade garnets may be used as an abrasive called garnet paper. It is less durable than corundum based sand paper, but it is less expensive.
Garnets are also used in abrasive blasting media, waterjet cutting, and abrasive powders. Garnet is a higher quality abraisive than the more commonly used and cheaper aluminum oxide. Silicon carbide and quartz sand are two close rivals of garnet abrasives.
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Garnet Geology
Some quick Garnet info:
Mohs' hardness: 6.5-8.5, Index of refraction: 1.73-1.889, Specific gravity: 3.5-4.3,
Streak: none, Cleavage: none, Fracture: conchoidal, Crystal form: dodecahedral
Garnet is a family of minerals having similar physical and crystalline properties. They all have the same general chemical formula, A3B2(SiO4)3, where A can be calcium, magnesium, ferrous iron, or manganese, and B can be aluminum, ferric iron, or chromium, or in rare instances, titanium.
GARNET, along with kyanite, (blades of kyanite can also be found in the rocks in this area) are two minerals that geologists use to interpret metamorphic conditions of heat and pressure that rock was subjected to during episodes of metamorphism and mountain-building.
As temperature and pressure in rock increase during metamorphism, certain minerals start to form. Chlorite is an indicator of low temperatures and pressures, followed by biotite as temperatures and pressures increase. Biotite, in turn, is followed by GARNET, staurolite, and kyanite at higher temperatures and pressures, and finally by sillimanite at the highest temperatures and pressures.
Geologists refer to this index mineral zonation as "regional Barrovian-type metamorphism"
Garnet appears in the rock at temperatures of 300 to 500 degrees Celsius, and 3 to 8 kilobars of pressure (equivalent to burial at depths of 10 to 30 kilometers below the surface).
→ → → → → → → → → → → TEMPERATURE → → → → → → → → → →
300 to 500 ° C. ° ℯ 550 to 800 ° C ° ℯ
Chlorite → Biotite → GARNET → Staurolite → Kyanite → Sillmanite
3 to 8 kb (10-30 km) ↑ 4 to 14 kb (12 to 45 km) ↑
→ → → → → → → → → → → → →PRESSURE → → → → → → → → → → →
Sequence of index metamorphic minerals that appear during progressive
regional Barrovian-type metamorphism in certain sedimentary rocks.
Geologic Processes
Garnets are a commonly identified index mineral. When higher grade metamorphic processes occur, garnets are often formed. They are therefore commonly present in schists and gneisses(see below). Radiometric dating of the garnets (using U-Pb, Rb-Sr, and Sm-Nd) can be used to determine the age of the rocks were formed in. Once the age of the rock is known, the cooling speed can be determined by analyzing the Sm-Nd decay.
Since garnets are formed when high temperatures and/or pressure is a factor, geologists often use garnets as a gauge of the amount of temperature and pressure that was present during their formation.
Because of this, garnets are known as the historians of the minerals. Most are formed by standard metamorphic processes. Others, however, are formed by being rolled between two moving surfaces. This rolling can cause them to pick up and preserve lower grade metamorphic rocks that would normally be destroyed by higher processes such as the ones that form garnets . This can give geologists valuable information about how and where the rocks were formed.
Metamorphic Rock
The formation of garnets always takes place in metamorphic rock. A metamorphic rock is either a sedimentary or igneous rock which has been changed, or metamorphosized, by some force. The most common forces are tremendous heat, pressure or some combination of both. As the rocks change, conditions might form garnets inside the metamorphic stones. As stated above, garnet is commonly found in stones like schist and gneiss.
SCHIST is 
a metamorphic rock that comes in almost infinite variety, but its main characteristic is hinted at in its name: schist comes from the ancient Greek for schist is a rock formed by dynamic metamorphism at temperatures and high pressures that aligns the grains of mica, hornblende and other flat or elongated minerals into thin layers, or foliation. At least 50 percent of the mineral grains(such as mica) in schist are aligned this way. Less than 50 percent makes the rock gneiss.
GNEISS, also a metamorphic rock, can be Grey or pink in color but with dark streaks and layers. It has a medium to coarse-grained texture, characterized by discontinuous, altering light and dark layers, the former usually having a coarsely granular texture while the latter, which often contains mica, may be foliated. In addition, gneiss tends to be banded on a large scale with layers and streaks of darker and lighter coloured gneiss. Granite and quartz veins and pegmatites are common.
There is however a second way that garnets could be formed, called Grinding, although it is not as common as formation by usual, metamorphic processes.
Grinding
While all garnets are formed in metamorphic rock, not all of them are formed by the processes that made the metamorphic rocks.
Once two metamorphic rocks have been formed, they lay in the earth next to each other like separate layers on a cake. As the earth shifts and moves, these metamorphic rocks might grind against each other. As this grinding happens, garnets could be formed. Garnets formed from the grinding of metamorphic rocks often contain smaller chunks of metamorphic rock inside them, marking them as different from garnets that were formed along with the metamorphic rock that they are found inside.
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Note: While not required, A PHOTO (of YOU if you wish) at the cache location is always appreciated,
AND CAN BE USED IN PLACE OF YOUR ANSWER(S).
TO LOG THIS CACHE:
Follow the instructions below and
Send Me An E-mail With The ANSWER to AT LEAST ONE of the Questions That Follow: (OR post a photo as noted above).
Please do not post the answers in your log! Please send the answers the same day you log the find.
Proceed to the posted coordinates. 
At the coordinates you will find a good-sized rock outcrop in the ground. → →
1.) Garnet varieties are found in many colors including red, burgandy, orange, yellow, green, blue, purple, brown, black, pink and colorless.
DESCRIBE THE COLOR(S) of the GARNETS YOU CAN SEE EMBEDDED IN THE ROCK
AT THE COORDINATES? (1)=_________________________________________.
2.) GARNETS can be found as well-formed crystals, or may appear as non well-formed deposits in the rock substrate. 
← (see photo examples) →
← well-formed crystal . . . . non well formed deposits →
FROM YOUR OBSERVATION : ARE THE GARNET DEPOSITS THAT YOU CAN SEE AT THE COORDINATES WELL-FORMED CRYSTALS OR NOT? (2)=_________.
***A REMINDER - IT IS AGAINST FEDERAL LAW AND NATIONAL PARK REGULATIONS TO COLLECT, REMOVE, OR TAMPER WITH ROCKS AND MINERALS FOUND IN THE PARK AND ALONG THE BLUE RIDGE PARKWAY!!***
3.) Both mica schist and gneiss are found in this area (see definitions and photo examples of
both above under Metamorphic Rock).
WHAT DO YOU THINK THE ROCK AT THIS LOCATION IS? (3)=_______________.
NOTE: I ask that you email your answers to me on the same day that you post your log.
(This does not have to be the day you visit, just the day you log the find on the computer.)
I also ask that you do not log a “found it” log unless you have actually visited the earthcache site and sent the answers to me. The only person who really benefits from your visit is YOU.
Thank you for visiting the Garnets at Craggy Gardens EarthCache and learning a bit about earth science.
Happy Caching and Enjoy your travels!
Impressive FTF HONORS go to..Caching Fool !!!(for hiking in due to ice & snow still there!)
I hope you enjoy your visit to this Blue Ridge Parkway EarthCache.
Permission for this cache has been granted by The National Park Service.
I would like to thank the National Park Service (The Blue Ridge Parkway) United States Department of the Interior, for their approval of this EarthCache. Remember: All EarthCache sites developed must have prior approval of the landowners before submission.
NOTE: All plants, animals, and other resources in the park are protected. You are allowed to gather edible fruits, nuts, & berries for your personal consumption only. Please stay on established trails.
Please remember that rock and mineral collecting is NOT PERMITTED along the parkway.
I used the publication "A Geologic Adventure Along The Blue Ridge Parkway in North Carolina" (Bulletin 98, North Carolina Geological Survey Section, Department of Environment and Natural Resources) for much of the information included here, after calling and obtaining permission to do so from Mike Medina of The North Carolina Geological Survey.
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