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Granitic Pegmatite?
  
  Index -> What is it? - Where is it from?
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PegmatiteAppreciator




Joined: 29 Oct 2024
Posts: 4
Location: Virginia

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PostPosted: Oct 31, 2024 21:17    Post subject: Granitic Pegmatite?  

Hello Folks,

I have a property in Bedford Virginia which is a county known to have some pegmatite. There are at least 3 mines close by with documented finds of the substance.
I have a lot of blue quartz on my property, and these rocks that have a mixture of feldspar, blue and clear quartz, and muscovite. There might be some other minerals mixed in there as well like tiny tourmalines and some kind of amphibole. The biggest reason I think I have pegmatite on my property is the presence of quartz prisms in close proximity to this type of rock. I find full prisms by the creek bank and bed and some 250 yards above that near my garden. I also find some partial prisms/quartz with faces.

Some of what I find seems to look similar to the North Carolina Crabtree pegmatite- only with a more blue-ish appearance instead of emerald.


I also have what some geologists have told me is diabase. Magnets stick to all of those specimens, and they have rust colored rinds. Most are roundly weathered and I’ve cut a few. I don’t have any bubbles in them like basalt does so I’d like to think they’re intrusive. Some geologists say that blue quartz is a basement rock around here.

One of the most interesting things about this diabase (apart from the silvery spots in them), is the fact that under a digital microscope, you can see what appears to be blue quartz in a polished slab.
Another interesting point is that all of the specimens I’m finding have these iridescent specks in them. This includes blue quartz, clear, yellow and red hematoid quartz, and the diabase. I’m thinking maybe they could be either incredibly fine specs of biotite mica, chromite, or brookite due to the blue quartz. I’m no expert- just hungry for knowledge and I’m here to learn.

What do you all think? If what I have isn't a type of pegmatite, how else are the quartz prisms forming? I probably have over 200 pictures of different specimens so its hard to show the big picture through a forum post and hard to decide what to post. I realize this is a bit of an overload.
Are there resources to view documented volcanic activity in Virginia?
Thanks in advance to any and all insight offered.



PicGrid_20241025_12310953.jpg
 Description:
 Viewed:  882 Time(s)

PicGrid_20241025_12310953.jpg



PicGrid_20240618_20480556.jpg
 Mineral: Not a mineral but diabase
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: roughly 10cmx12xcm slab
 Description:
 Viewed:  871 Time(s)

PicGrid_20240618_20480556.jpg



20240907_180539.jpg
 Mineral: Multiple minerals in diabase
 Description:
This was taken by a digital microscope. It is a well-sanded piece where the silver-colored spot had been worn down some. This diabase looking stuff has a lot of different tiny minerals like olivine and small tourmalines I have pictures of elsewhere.
 Viewed:  878 Time(s)

20240907_180539.jpg



signal-2024-03-14-22-21-36-682.jpg
 Mineral: Blue quartz, feldspar, and black mica
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 6 cm thick and 11 cm long on the center piece
 Description:
 Viewed:  876 Time(s)

signal-2024-03-14-22-21-36-682.jpg



Screenshot_20241005_201702_Chrome.jpg
 Mineral: This is a screenshot of the NC Crabtree pegmatite for comparison purposes
 Locality:
Crabtree Creek, Mitchell County, North Carolina, USA
 Dimensions: in description
 Description:
 Viewed:  875 Time(s)

Screenshot_20241005_201702_Chrome.jpg



20241005_202639.jpg
 Mineral: Blue quartz, feldspar, and black mica
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 5 cm x 5cm
 Description:
 Viewed:  872 Time(s)

20241005_202639.jpg



20241005_115621.jpg
 Mineral: Blue quartz, feldspar, and black mica
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 3 cm x 2 cm
 Description:
 Viewed:  871 Time(s)

20241005_115621.jpg



20230610_141050.jpg
 Mineral: Blue quartz, feldspar, and black micah
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: Whole slab is maybe 30cmx20cm
 Description:
 Viewed:  871 Time(s)

20230610_141050.jpg



2020_0101_002417_053.JPG
 Mineral: Quartz
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 8cmx6cm
 Description:
This is a digital microscope photo of one point of a quartz prism cluster. Maybe prism isn't even the right term but I notice some folks call a random chunk of quartz a crystal so I figured I'd stick to the former term.
 Viewed:  870 Time(s)

2020_0101_002417_053.JPG


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PegmatiteAppreciator




Joined: 29 Oct 2024
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Location: Virginia

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PostPosted: Oct 31, 2024 21:25    Post subject: Re: Granitic Pegmatite?  

I'm used to posting pictures much more quickly on forums through my cell phone but this interface is a bit slower for me. I posted some pictures I didn't mean to since I didn't name the files. I'll post a few more pictures of the diabase here.

These are more to prove corroboration/volcanic activity here. You can see the magnets sticking all over the big slab in the picture.



PicGrid_20240618_21035947.jpg
 Mineral: Not a mineral but diabase
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 12cmx10cm
 Description:
I had meant to post a picture of this small slab I cut in the previous post.
 Viewed:  867 Time(s)

PicGrid_20240618_21035947.jpg



20230917_184131.jpg
 Mineral: Silvery metal spots- I'm not sure
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 2mm
 Description:
 Viewed:  865 Time(s)

20230917_184131.jpg



20230918_083253.jpg
 Mineral: More diabase
 Locality:
Bedford, Bedford County, Virginia, USA
 Description:
 Viewed:  867 Time(s)

20230918_083253.jpg


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PegmatiteAppreciator




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Location: Virginia

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PostPosted: Nov 02, 2024 08:49    Post subject: Re: Granitic Pegmatite?  

I wanted to post a few more pictures of my findings. I'll probably add more as I have time.


20240901_110004.jpg
 Mineral: Quartz
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: ~3cmx4cm
 Description:
There are many faces along this piece, triangle imprints and other things. There is also a conchoidal fracture that looks like it was deliberately hit, but who knows. I have found arrowheads in the same creek I found this, as well as arrowheads in the field above.
 Viewed:  703 Time(s)

20240901_110004.jpg



2020_0101_003830_055.JPG
 Mineral: Quartz
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 3cmx4cm
 Description:
Digital microscope picture of some of the imprints.
 Viewed:  705 Time(s)

2020_0101_003830_055.JPG



2020_0101_003942_057.JPG
 Mineral: Quartz
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: Not sure very small like 1-2mm
 Description:
Another close up of some of the multiple facets on this piece.
 Viewed:  707 Time(s)

2020_0101_003942_057.JPG



2020_0101_004215_062.JPG
 Mineral: Quartz
 Locality:
Bedford, Bedford County, Virginia, USA
 Dimensions: 2mm? The fracture I mean
 Description:
Up close look at the fracture
 Viewed:  709 Time(s)

2020_0101_004215_062.JPG


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James Catmur
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Joined: 14 Sep 2006
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PostPosted: Nov 03, 2024 13:25    Post subject: Re: Granitic Pegmatite?  

It might make sense to talk to your local university's geology department
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