PegmatiteAppreciator
Joined: 29 Oct 2024
Posts: 4
Location: Virginia
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Posted: Oct 31, 2024 21:17 Post subject: Granitic Pegmatite? |
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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.
Description: |
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Viewed: |
882 Time(s) |
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Mineral: | Not a mineral but diabase |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | roughly 10cmx12xcm slab |
Description: |
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Viewed: |
871 Time(s) |
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Mineral: | Multiple minerals in diabase |
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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. |
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Viewed: |
878 Time(s) |
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Mineral: | Blue quartz, feldspar, and black mica |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 6 cm thick and 11 cm long on the center piece |
Description: |
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Viewed: |
876 Time(s) |
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Mineral: | This is a screenshot of the NC Crabtree pegmatite for comparison purposes |
Locality: | Crabtree Creek, Mitchell County, North Carolina, USA | |
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Dimensions: | in description |
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Viewed: |
875 Time(s) |
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Mineral: | Blue quartz, feldspar, and black mica |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 5 cm x 5cm |
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Viewed: |
872 Time(s) |
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Mineral: | Blue quartz, feldspar, and black mica |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 3 cm x 2 cm |
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Viewed: |
871 Time(s) |
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Mineral: | Blue quartz, feldspar, and black micah |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | Whole slab is maybe 30cmx20cm |
Description: |
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Viewed: |
871 Time(s) |
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Mineral: | Quartz |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 8cmx6cm |
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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. |
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Viewed: |
870 Time(s) |
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PegmatiteAppreciator
Joined: 29 Oct 2024
Posts: 4
Location: Virginia
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Posted: Oct 31, 2024 21:25 Post subject: Re: Granitic Pegmatite? |
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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.
Mineral: | Not a mineral but diabase |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 12cmx10cm |
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I had meant to post a picture of this small slab I cut in the previous post. |
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Viewed: |
867 Time(s) |
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Mineral: | Silvery metal spots- I'm not sure |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 2mm |
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Viewed: |
865 Time(s) |
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Mineral: | More diabase |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Description: |
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Viewed: |
867 Time(s) |
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PegmatiteAppreciator
Joined: 29 Oct 2024
Posts: 4
Location: Virginia
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Posted: Nov 02, 2024 08:49 Post subject: Re: Granitic Pegmatite? |
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I wanted to post a few more pictures of my findings. I'll probably add more as I have time.
Mineral: | Quartz |
Locality: | Bedford, Bedford County, Virginia, USA | |
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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. |
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Viewed: |
703 Time(s) |
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Mineral: | Quartz |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 3cmx4cm |
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Digital microscope picture of some of the imprints. |
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Viewed: |
705 Time(s) |
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Mineral: | Quartz |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | Not sure very small like 1-2mm |
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Another close up of some of the multiple facets on this piece. |
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Viewed: |
707 Time(s) |
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Mineral: | Quartz |
Locality: | Bedford, Bedford County, Virginia, USA | |
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Dimensions: | 2mm? The fracture I mean |
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Up close look at the fracture |
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Viewed: |
709 Time(s) |
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