jamesp
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Post by jamesp on Feb 4, 2015 6:30:38 GMT -5
Interesting how ruby 'flows' in zoisite. Like crystals remelted and possibly in shear
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Deleted
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Post by Deleted on Feb 4, 2015 6:56:58 GMT -5
Gorgeous. It surprises me how much pink and green there is in the rock world. The thulites I have do not have the visible crystal structure that this stone has and I think I like the look of this stone better. Jim
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jamesp
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Post by jamesp on Feb 4, 2015 8:35:00 GMT -5
Gorgeous. It surprises me how much pink and green there is in the rock world. The thulites I have do not have the visible crystal structure that this stone has and I think I like the look of this stone better. Jim Some crystals in matrix are older, and some in newer, than the matrix they are in. Metamorphosis does weird stuff to any matrix/crystal combo. Fused sand like quartzite can have all kinds of effects on crystals that were fused with the sand. Garnet crystals are a good candidate for such studies since they are common and have deep color for visual aid. In shear situations garnet crystals can 'bulldoze' material in front of them due to their toughness/hardness. From Wiki: A porphyroblast is a large mineral crystal in a metamorphic rock which has grown within the finer grained groundmass. Porphyroblasts are commonly euhedral crystals, but can also be partly to completely irregular in shape. The most common porphyroblasts in metapelites (metamorphosed mudstones and siltstones) are garnets and staurolites, which stand out in well foliated metapelites (such as schists) against the platy mica matrix. A similar type of crystal is a phenocryst, a large crystal in an igneous rock. Porphyroblasts are often confused with porphyroclasts, which can also be large outstanding crystals, but which are older than the matrix of the rock. If a porphyroblastic mineral has small inclusions of minerals within it, the mineral is described as poikiloblastic. This observation can help interpret deformation history. A rock which has many porphyroblasts is described as having a porphyroblastic texture. As porphyroblasts grow, the foliation may be preserved as oriented inclusions trapped by the porphyroblast as it overgrows them, and this is helpful for tracking changing deformation planes. In metamorphic rocks that experience deformation during metamorphism, porphyroblasts may grow before, during, or after the phase of deformation recorded by the matrix minerals. The relationship of porphyroblast growth to deformation is typically evaluated by comparing the shape orientation of trails of mineral inclusions in the porphyroblast to the matrix fabric. Some garnet porphyroblasts contain various curving trails of quartz and other mineral inclusions. The question of whether porphyroblasts (and garnet in particular) rotate during metamorphism and deformation has long been the subject of debate. Whereas most researchers are convinced that porphyroblast may rotate during deformation, some believe that porphyroblasts do not rotate.[citation needed] As they grow, the foliation is preserved in their crystal structure, which is helpful for tracking changing deformation planes.
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jamesp
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Post by jamesp on Feb 4, 2015 8:43:24 GMT -5
porphyroblastic gneiss with some little garnet crystals !!(from google images)
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Post by gingerkid on Feb 8, 2015 10:58:17 GMT -5
Love the pic you posted of the garnet porphyroblast, jamesp! Please check out Mr. Richard Hughes' website with pics of tsavorite garnet porphyroblasts, and a nice read about Mr. Campbell Bridges. I'd love to get my paws on a tsavorite porphyroblast. www.ruby-sapphire.com/tsavorite-untamed-beauty.htm
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jamesp
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Post by jamesp on Feb 8, 2015 11:06:31 GMT -5
Love the pic you posted of the garnet porphyroblast, jamesp! Please check out Mr. Richard Hughes' website with pics of tsavorite garnet porphyroblasts, and a nice read about Mr. Campbell Bridges. I'd love to get my paws on a tsavorite porphyroblast. www.ruby-sapphire.com/tsavorite-untamed-beauty.htmI figured that one would put ya to drooling, did me. talk about some hoss garnets. Will look up Mr. Campbell Bridges
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Post by gingerkid on Feb 8, 2015 11:23:14 GMT -5
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jamesp
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Post by jamesp on Feb 8, 2015 11:42:59 GMT -5
Wow, what a shame. sob's, should be life for a life. easier on us tax payers. Bet the jails there are not cozy
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Post by gingerkid on Feb 8, 2015 12:05:15 GMT -5
I agree, and it took too long for his family to receive any closure and justice. His passing was also great loss for the geological and gemological communities. Mr. Bridges also specialized in Tanzanite and was a consultant to Tiffany's. www.tsavorite.com/history/tanzanite.html
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jamesp
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Post by jamesp on Feb 8, 2015 16:13:56 GMT -5
This one with a blacker background, probably hornblende, pink felspar colored spots. water intrusion stained the outside on this small pebble
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Post by gingerkid on Feb 8, 2015 16:34:54 GMT -5
That's really pretty! Have you asked garock and pghram to please check out your thread to see if they may know what the material is called, jamesp?
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jamesp
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Post by jamesp on Feb 8, 2015 17:48:56 GMT -5
That's really pretty! Have you asked garock and pghram to please check out your thread to see if they may know what the material is called, jamesp? I need to, Frankie and Rich know their stuff.
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Post by gingerkid on Feb 9, 2015 13:00:11 GMT -5
May need to holler a little louder, jamesp. garock!! pghram!! Sure would like to know what is in the materials, and if the beautiful green piece with the red dots is a garnet porphyroblast.
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garock
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Post by garock on Feb 9, 2015 17:32:20 GMT -5
I am not sure about the red spots. I would think if it was feldspar it would have a certain "sheen" to it. Up on Chunky Gal there is rocks green with pink sapphires but the ones I have collected are tiny sapphire crystals in the green so called zoisite. Shame they are not large sapphires. I am leaning more toward garnets that have formed and then reheated and sort of mushed the garnets. Only thulite I know is found at the Ray Mine in North Carolina. The red does seem to fit thulite. I am up in the air about the identity ! Sorry ! I do believe the black is hornblende as others have said.
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Post by gingerkid on Feb 9, 2015 21:47:50 GMT -5
Thank you, garock! Where is Chunky Gal?
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Post by broseph82 on Feb 10, 2015 14:29:49 GMT -5
Thank you, garock! Where is Chunky Gal? do you learn nothing from fantastic5 and my trips? Ha ha it's near lake Chatuge, Nc
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garock
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Post by garock on Feb 11, 2015 9:41:32 GMT -5
Chunky Gal or Ruby Knob is in the National Forest due west of Franklin, NC on US 64. Going west past Buck Creek Rd, which is on the right, to the first forest road to the right. Just as you turn to the right take an immediate left and go up this very meandering sharp curves to a parking area. If I remember right the a trail leading to the back right goes to the collecting area. Not the best path but ok. You will be on a ridge with lots of boulders broken up and digging spots. I am not sure if the Forest Service still allows digging, better check on this. The Forest Service can be pretty mean about digging. There is greyish white to green granite like material with rubies and pink sapphires. The green material takes a pretty good polish and is really fantastic with the corundum mixed in. A sledge hammer is highly recommended. Can't miss the area forgetting this material. Make sure you are aware of your location and remember how to leave. Some collectors venture down from the top to toward the bottom. In places it is pretty steep. Five gallon buckets get heavier with each step coming back up ! In late spring and summer, storms hit the are nearly everyday. When they, I would recommend to leave. One trip we make it had been raining cats and dogs all day. About 2:30 pm, I raised up an a dog belonging to another collector came running up the ridge "lick-a-dy split. What's with the dog. 2 seconds later a lightning strike, so close we could feel the electricity and the click. I did not know I could tote 2 five gallon buckets of material so fast up the ridge and to the truck so fast ! I think we were just a few seconds behind the dog. This is the closest I have ever been to a lightning strike. Several rock clubs in the southeast have fieldtrips to Chunky Gal. Might be a good idea to go the first time with a club or with someone who has been to the location previously. Late winter and early spring, not so much rain. Went once with a club fieldtrip, arrived late, collectors all over the area, most not having good luck but my wife, a collector from Massachusetts and I sat down and began checking out our spot. We found about 2 dozen pink sapphires. The best trip I have ever had. You never know !
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jamesp
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Post by jamesp on Feb 14, 2015 3:23:13 GMT -5
I am not sure about the red spots. I would think if it was feldspar it would have a certain "sheen" to it. Up on Chunky Gal there is rocks green with pink sapphires but the ones I have collected are tiny sapphire crystals in the green so called zoisite. Shame they are not large sapphires. I am leaning more toward garnets that have formed and then reheated and sort of mushed the garnets. Only thulite I know is found at the Ray Mine in North Carolina. The red does seem to fit thulite. I am up in the air about the identity ! Sorry ! I do believe the black is hornblende as others have said. fantastic5 gingerkid broseph82 and Tonya Going back to this 'spotted quartzite' location on the Tallulah River tomorrow Frankie. This time about 12 river miles upstream close to Tate City. Talullah River Road flanks the river closely for miles going north towards Tate City and is only 10-20 feet higher than the river. The rocks in the river look much less rounded and looks like lots of flat plate quartzite in the river that may be source material for the cobbles 12 miles downstream. Always liked the mountain quartzite, most of the quartzite in this post is very dense, the cobbles downstream were somewhat fractured and stained. So looking for material closer to the source well upstream and less abused. May also be hornblende needles in quartz/ite that resemble black tourmaline needles. Some fancy hornblende mixes. A view of the spot I am heading to tomorrow, note flat plate material in river, I believe you can drive your car in the river here(a crossing): Have found many colors of quartzite in the TVA lakes while they were at low water level in the form of chips left by native man. Some were fine grade with no fractures and crazy color shades, many with mica specs that glitter. I hope to check out the zoisite spot. May have found it on google earth. Heading west on 64 past Buck Creek Road it looks like you turn right on the next forestry road. Then an immediate left for about a mile to the top of a ridge with a big parking lot. Looks like the ridge trail to the right leads NE to a boulder field about 1/4 mile away sloping to the right of the ridge and down hill a bit. Am I close ??
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Deleted
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Post by Deleted on Feb 14, 2015 5:44:44 GMT -5
My kinda place. Jim
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jamesp
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Post by jamesp on Feb 14, 2015 8:06:40 GMT -5
Probably flatter than Greybull, and warmer. But you got the rocks
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