Joe,

Are you calling the tourmaline in these specimens fluor-dravite instead of schorl?

D.

Well, I just started playing with some of the pegmatite rough I collected at the Crabtree over 10 years ago and I'm having a Blast!
Great fun! Beautiful interesting material full of surprises!

Now that I am cutting and working the material I hope to get some good pictures of the tourmaline. Preliminary results do not change what I've mentioned above.

In the first picture the one on the far left is a broken egg.
And calling the one on the far right an egg would be stretching it.
But the rest of the pictures are eggsactly what I'm talking about.

As to the fluor-dravite conversation, I think it is nearly impossible without comprehensive scientific analysis to determine the type of tourmaline. Coloration can be a clue, but is not definitive.  Is there published analysis of crabtree tourmaline?  Would love to see it if you know of it.  I can only state that the VAST majority of tourmaline I've seen over the years from Crabtree is jet black, indicating schorl.  I've seen very little of the brown.  I have seen the brown in muscovite from the Ray mine and other mines in the Black Mountain range.  Not saying fluor-dravite isn't there, but wondering how prevalent it is and how that was determined.

Yes, yes, yes, Could not agree with you more, Laurie. 
I, of course, do not have the ability to do the comprehensive analysis needed to answer this question. And I have always looked at the tourmaline from the Crabtree as schorl. But now, finally getting around to taking a closer look, I would say there is very little schorl.

As you can see, from the article cited by Dennis, Fluor-Dravite is a very "new" mineral, 2011. In the article from Mindat that I'm linking you to below it is stated that The Big Crabtree is the type locality for this new tourmaline classification. In the Clarke,Hawthorne, Ottolini article they talk about finding only minute millimeter sized grains of the Fluor-Dravite in limited contact areas, but in the Mindat article they tested all different specimens of the tourmaline and report that it was "all" this "new" dark brown tourmaline, and that is exactly what I am finding.
Here is the Mindat link,
https://www.mindat.org/a/best_fluordravite

With my very limited scientific knowledge and abilities, ,
I can safely say that at least 50% of what I'm finding in my specimens from the Crabtree are a dark brown translucent tourmaline, sometimes transitioning to green, and am guessing the percentage to be much higher. It is definitely not all schorl.
Some of the tourmaline crystals have a brown translucent 1-2mm thick "rind" on the outside and a degraded opaque black interior, so I do not have any idea what is going on there.

I need to make some good specimen pieces for the tourmaline and hope to get working on that soon, but here are some really poor pictures that you might be able to see some of what I am talking about.
The first picture is of some random samples of Crabtree pegmatite. With a good light and a loupe you can see that 'All' the tourmaline in those pieces are a dark translucent brown, or Fluor-Dravite for lack of  a better name.
The last two pics are of a thin section I cut. Sorry about the quality of the specimen and pictures, but this is very typical of what I am seeing in the tourmaline once cut.
I want some Schorl! I'm looking for schorl in this stuff, but don't know if I have found any yet?
This really is a great topic for discussion. Dennis and I have been batting it around for a few years, and I am finally getting around to taking a closer look. Several years ago, after talking with Dennis, I went in search of scientific research done on schorl and dravite and found an article that concluded there could be a dozen different chemical signatures between the schorl and dravite series and that it would take years to identify and distinguish them all, if any one wanted to. Hopefully more work will be done on specifically the tourmaline from The Big Crabtree. 

I've been cutting a lot of the tourmaline. It is very brittle and a lot of the interior is totally degraded and fractured. A grainy opaque black like ash that will come off on your fingers. Not all, but a lot.
I cut some 2mm thick slabs and had to grind them down to less than .5 of 1mm before any light would pass through the tourmaline to see a color. Mostly browns, but a lot of greens, too, and I guess this is normal and acceptable for Schorl? If these color variations are acceptable, it's textbook Schorl.
One thing I did come to realize while looking at all the material is you don't need to cut and grind the tourmaline down to see the "hidden" color. The root beer color staining in the surrounding quartz/albite is coming from the tourmaline, and that's what color the tourmaline really is.
Some examples of the staining in this next polished piece. You can also see how degraded the interior of the tourmaline is.

I would love to see more chemistry done on the tourmaline from Crabtree before I die, but I don't really know why, when Schorl seems to fit the bill perfectly, almost.
Sorry to raise all your hairs but totally translucent dark brown crystals were throwing me off.
I am going back to calling it Schorl until someone comes up with something better. 

Joe,

Great research on the Schorl/Dravite/Hornblende.  I looked at a number of photos of hornblende, both crystals and cross-section slides. It does appear very similar to schorl, but seems to be less triangular (bowed triangle) than schorl.  Hornblende xls. that I have found and/or seen in the Spruce Pine area were very blocky looking and not as slender as the Crabtree schorl xls. 

I may continue to call it schorl in my records but add a brief note regarding fluor-dravite since it was described at the Crabtree mine.

And: Is the schorl found at numerous other Spruce Pine district mines schorl, fluor-dravite, or hornblende?

Dennis

Joe,

I bought "Down the Crabtree" several years ago and found it informative.  I actually knew several of the people he talked about when I lived in Spruce Pine in the 1960s.  His book has a lot of local info, but is not as expansive as it could have been.

I did a quick search for Schorl and or 'Tourmaline' for the Spruce Pine mining district (Avery, Mitchell, & Yancey counties) and there are quite a few listed.  Many of these localities also have 'Hornblende' listed, but the hornblende is restricted to the mines where the wallrock was hornblende schist or hornblende gneiss, not mica schist or granite pegmatite ('alaskite').....if that makes any difference.

I'm sure the locations that just indicated 'tourmaline' were older mines where no analyses were done on the specific minerals.  It's like saying there was feldspar, but not orthoclase, plagioclase, perthite, etc.

Dennis