New Mineral Named After GIA’s John Koivula
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 Post subject: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 3:56 am 
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Nail-like hematite in quartz.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 3:57 am 
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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 12:37 pm 
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I dare say, this beats the gold wires from one of your previous posts.
Where are you finding this stuff?


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 1:19 pm 
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Barbra Voltaire wrote:
I dare say, this beats the gold wires from one of your previous posts.
Where are you finding this stuff?

Almost all my quartz specimens are provided by sellers in Donghai County.I keep in touch with a lot of them. So if they have something interesting, they will let my know.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 1:54 pm 
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These are exceptional! Wonderful photos as well, very crisp. I have been seeing some similar forms in Moroccan agate recently, but they really shine in such a transparent background. What are you using the photograph them?

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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 1:59 pm 
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Stephen Challener wrote:
These are exceptional! Wonderful photos as well, very crisp. I have been seeing some similar forms in Moroccan agate recently, but they really shine in such a transparent background. What are you using the photograph them?

Just a microscope and my cellphone, a polarizing filter is also needed.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 3:54 pm 
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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 4:26 pm 
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You can "count the rings" on some of these. I wonder if each one corresponds to a separate event?


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 6:13 pm 
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I've seen nail-head spicules before, they do not contain solid inclusions like hematite in the "tapered void".
Found some pics of nail-head spicules here:
http://www.ggtlaboratory.com/content-Sy ... 994-2.html


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 6:22 pm 
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dchallener wrote:
You can "count the rings" on some of these. I wonder if each one corresponds to a separate event?

That's quite possible.I can find some nails with separate rings in the stone. I'll take some pictures later.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 6:55 pm 
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The nail heads in the link you posted were in synthetic quartz and have quite a different character than yours, no?


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 7:09 pm 
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Barbra Voltaire wrote:
The nail heads in the link you posted were in synthetic quartz and have quite a different character than yours, no?


Yes, that's why I don't think the inclusions in my stone are nail-head spicules.
As nail-head spicules are caused by rpid and disturbed growth,they look quite the same in natural or synthetic stones.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 8:07 pm 
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Interesting that I can find no previous instances of inclusions like these in anything I have personally seen, or in the literature. Sort of like the previous "gold" inclusions.

Apparently Donghai County has some famous deposits containing large quartz crystals. From the quartz deposit has emerged industries that make high tech products out of quartz silica base. The question is, which is the source of the fascinating samples you are finding.

Interesting to see, thanks for posting. I am looking forward to more interesting finds.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 11:13 pm 
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1bwana1 wrote:
Interesting that I can find no previous instances of inclusions like these in anything I have personally seen, or in the literature. Sort of like the previous "gold" inclusions.

Apparently Donghai County has some famous deposits containing large quartz crystals. From the quartz deposit has emerged industries that make high tech products out of quartz silica base. The question is, which is the source of the fascinating samples you are finding.

Interesting to see, thanks for posting. I am looking forward to more interesting finds.

The stone is most possibly from Brazil or Madagascar.
Actually,something similar has been reported in this thread:
viewtopic.php?f=21&t=9303
The images are gone now,but as I remembered,the inclusions are also nail-like(maybe not exactly like those in my specimen),and the host stone is also amethyst.


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 Post subject: Re: Nail-like hematite in quartz
PostPosted: Sat Feb 23, 2019 11:37 pm 
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With a little research, I found a blog from 2010 written by Callan Bentley who is an assistant professor of geology at Northern Virginia Community College.
Callan wrote:
28 October 2010
The tale of the hammerheaded copper tadpole
Okay, now just what the heck is going on in these pictures?
Image
Image
Image


The photos are different views of the same crystal. It is a broken hexagonal prism of quartz, fading to amethyst at the distal end, found by Doug Dupin of northwest DC during the excavation that led to the Palisades Museum of Prehistory. The crystal is about 3.5 cm long, and 1 cm wide. The curiously-shaped inclusions you see in these photos are ~2 mm long.

Last year, Doug and I photographed the crystal using my new Nikon microscope, and Doug put it up on some mineralogy discussion boards, but got no positive ID. The issue came up again last Saturday night, at a homebrew keg-tapping party at Doug’s museum, where I met Doug’s friend Maria Stenzel, a National Geographic photographer. Maria had also taken a photo of the crystal with her macro lens, and has willingly shared it here*: it’s the last of the three images above. It offers a nice contrast to my images — while hers is sharper and you can see more focused “shape” detail, mine more accurately reflect the colors: the quartz is pinkish purple, more so towards the tip, and the inclusions appear “coppery” in luster and tone.

Key observations: the “hammerhead” shapes are distal to the pointed “tail” of these structures, which are more proximal to the core of the crystal prism. The tails all start at the same depth, and the semi-circular hammerheads all occur at the same “shallower” level in the crystal. Some of the inclusions are “double-headed” that merge into a single “tail.” There are also small spherical coppery balls present, apparently made of the same material but with a different shape.

What is the origin of these inclusions? Why are they shaped in this curious way?

Any insights, well-founded or wildly-speculative, would be welcome. Let us know what you think in the comments section below.

Click here for direct link to blog


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