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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 10, 2017 05:11 Post subject: Super thin hematite inclusions in amethyst |
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Super thin hematite inclusions in amethyst:
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Tobi
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Joined: 07 Apr 2009
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Location: Germany
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Posted: Nov 10, 2017 07:03 Post subject: Re: Super thin hematite inclusions in amethyst |
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zbhjzm wrote: | Super thin hematite inclusions in amethyst: | That looks really beautiful. But could you tell us a bit more: Where's the amethyst from? How wide is the field of view on that photos? Is it confirmed that the inclusions are hematite? How does the whole specimen look?
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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 10, 2017 08:00 Post subject: Re: Super thin hematite inclusions in amethyst |
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Tobi wrote: | zbhjzm wrote: | Super thin hematite inclusions in amethyst: | That looks really beautiful. But could you tell us a bit more: Where's the amethyst from? How wide is the field of view on that photos? Is it confirmed that the inclusions are hematite? How does the whole specimen look? |
Hi Tobi ,
The amethyst is most probably from Brazil.
The inclusions have been magnified 64-160 times.
Judging from the inclusion's form and color, hematite is my best guess.
Here is the pic of the whole specimen:
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braulioff
Joined: 14 Jul 2014
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Location: Belo Horizonte - MG
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Posted: Nov 10, 2017 08:10 Post subject: Re: Super thin hematite inclusions in amethyst |
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I´ve been told most of these inclusions are goethite.
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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 10, 2017 08:45 Post subject: Re: Super thin hematite inclusions in amethyst |
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braulioff wrote: | I´ve been told most of these inclusions are goethite. |
I have specimens with goethite inclusions, they look quite different.
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John S. White
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Location: Stewartstown, Pennsylvania, USA
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Posted: Nov 10, 2017 10:09 Post subject: Re: Super thin hematite inclusions in amethyst |
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I would guess goethite. Hematite tends to be red in color in very thin crystals. And although some of these crystals are reddish, they are not the red of hematite.
_________________ John S. White
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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 10, 2017 11:38 Post subject: Re: Super thin hematite inclusions in amethyst |
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Actually the specimen is only partly purple, most of the inclusions are in the colorless part of the quartz and they are indeed red.
Though the inclusions are super thin ,still they look exactly like the hematite inclusions in the so-called " strawberry quartz".
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kakov
Joined: 24 Jul 2013
Posts: 39
Location: Madrid
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Posted: Nov 10, 2017 12:40 Post subject: Re: Super thin hematite inclusions in amethyst |
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Fantastic images! I am specially fan of the one with pampas landscape like goethite inclusions.
As “traditional” mineral collectors often feel certain aversion against the cutting and polishing of stones, the “inclusion world” falls out of our sight. But it is truly fascinating, so thanks a lot for sharing such images here! And please continue with this good habit (I have seen you have posted stuff previously as well).
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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 10, 2017 13:22 Post subject: Re: Super thin hematite inclusions in amethyst |
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kakov wrote: | Fantastic images! I am specially fan of the one with pampas landscape like goethite inclusions.
As “traditional” mineral collectors often feel certain aversion against the cutting and polishing of stones, the “inclusion world” falls out of our sight. But it is truly fascinating, so thanks a lot for sharing such images here! And please continue with this good habit (I have seen you have posted stuff previously as well). |
Thank you,I'll continue exploring the “inclusion world” with microscope and post pics when I find something interesting.
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John S. White
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Posted: Nov 11, 2017 05:59 Post subject: Re: Super thin hematite inclusions in amethyst |
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Sorry to have to disagree with you but to my eye the inclusions in the two quartzes are not "exactly" alike. Those in the so-called strawberry quartz are typical hematite red while the others, assuming that the color in the photo is true, are not. And judging from your photos in the first postings they are quite varied and range from reddish to brown, something I would not expect to see with hematite.
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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 11, 2017 07:14 Post subject: Re: Super thin hematite inclusions in amethyst |
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John S. White wrote: | Sorry to have to disagree with you but to my eye the inclusions in the two quartzes are not "exactly" alike. Those in the so-called strawberry quartz are typical hematite red while the others, assuming that the color in the photo is true, are not. And judging from your photos in the first postings they are quite varied and range from reddish to brown, something I would not expect to see with hematite. |
As I can not be sure what the inclusions are, it's always good to have different opinions, thank you~
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alfredo
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Posted: Nov 11, 2017 19:15 Post subject: Re: Super thin hematite inclusions in amethyst |
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To my eye, the first two photos do look like hematite inclusions, especially the red "stems" of those dendritic aggregates. Apparent variation in color towards the tips could be caused by some thin film effect between the hematite and the quartz, ie some surface film on the hematite or gap between the hematite and the quartz. Thin films are very difficult to check; we really don't have good technology to analyze thin films yet.
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John S. White
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Posted: Nov 11, 2017 20:55 Post subject: Re: Super thin hematite inclusions in amethyst |
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Hate to come on like a pedant but I can claim a certain amount of expertise on this subject as it has been a focus of quite a lot of study on my part and I am also particularly reluctant to challenge anything that Alfredo states, but the color of very thin hematite is quite distinctive and constant in my experience whereas that of goethite is not. Apart from the fact that the red in your photos is not a hematite red, the very fact that your photos show a wide range of color is, in my view, evidence enough to rule out hematite.
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alfredo
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Posted: Nov 11, 2017 22:11 Post subject: Re: Super thin hematite inclusions in amethyst |
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John, Would Raman spectroscopy work through quartz to distinguish the various iron oxide species, or would the quartz interfere?
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zbhjzm
Joined: 18 Dec 2016
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Posted: Nov 12, 2017 03:19 Post subject: Re: Super thin hematite inclusions in amethyst |
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John S. White wrote: | Hate to come on like a pedant but I can claim a certain amount of expertise on this subject as it has been a focus of quite a lot of study on my part and I am also particularly reluctant to challenge anything that Alfredo states, but the color of very thin hematite is quite distinctive and constant in my experience whereas that of goethite is not. Apart from the fact that the red in your photos is not a hematite red, the very fact that your photos show a wide range of color is, in my view, evidence enough to rule out hematite. |
Some of the inclusions do show a range of color, I don't know whether it's because they are too thin or because they are goethite. The only thing I can do is to take more photos.
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John S. White
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Posted: Nov 12, 2017 04:56 Post subject: Re: Super thin hematite inclusions in amethyst |
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Alfredo: I don't know the answer to that as I have very little experience with Raman which was not available to me when I was at the museum. The fineness of the crystals in this case might be more of a factor in preventing a reading and you also have to find someone with the instrument who is willing to take the time to identify something like this. One more thought, The nature of the crystals in this case also suggests, to me, goethite and not hematite.
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marco campos-venuti
Joined: 09 Apr 2014
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Location: Sevilla
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Posted: Nov 12, 2017 12:18 Post subject: Re: Super thin hematite inclusions in amethyst |
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John, is it possible to distinguish fibrous Hematite from fibrous Goethite with the naked eye? I mean not included in quartz but when they are in botryoidal shape. I suspect there is a bit of confusion, almost I'm not sure to understand the difference.
Usually inclusions in quartz are considered Hematite when flat (also elongated) and Goethite when strictly fibrous (for example the material that was sold as quartz with cacoxenite and looks to me as Goethite).
I'm sure Raman doesn't work on most inclusions in quartz, mainly because quartz strongly replace any included mineral.
I can post many examples from my collection.
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marco campos-venuti
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Posted: Nov 12, 2017 12:31 Post subject: Re: Super thin hematite inclusions in amethyst |
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Few examples of what I suppose is Hematite in Quartz. Mostly red, main characteristic is a flat crystal, more or less elongated.
All sample are from Brazil, difficult to say the exact place. How would say Rock Currier, probably Minas Gerais.
Last picture is an Amethyst Brazil Twin.
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Mineral: | Amethyst Brazil Twin with Hematite |
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marco campos-venuti
Joined: 09 Apr 2014
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Posted: Nov 12, 2017 12:41 Post subject: Re: Super thin hematite inclusions in amethyst |
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And here few examples of what I consider Goethite in Quartz. I'm not sure, just is what I use to call it. Mostly yellow and strictly fibrous, more abundant in Amethyst. All samples from Brazil.
The last is the material still commercialized as Quartz with Cacoxenite, but most people know is not. Similar but a phosphate.
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marco campos-venuti
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Posted: Nov 12, 2017 12:44 Post subject: Re: Super thin hematite inclusions in amethyst |
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And here is what we call Quartz with iron oxides, because we don't know what it really is. Also from Minas Gerais
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