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Scepters - (1)
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Amir Akhavan




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PostPosted: Jan 03, 2010 13:50    Post subject: Re: Scepters - (1)  

Oh, my question is already answered, thanks...
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PostPosted: Jan 03, 2010 14:02    Post subject: Re: Scepters - (1)  

Well I am running out of scepter photos to share with you (do I hear a sigh of relief?) but I have to include another of my favorites. This one is from the Tipling mine, Dhading district, Nepal. It is 8.5 cm high. What is unusual about this one is the clear tip on a typical chlorite-infested stem


DSCN1513.JPG
 Description:
Close-up of the tip.
 Viewed:  15394 Time(s)

DSCN1513.JPG



Crystal2.jpg
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 Viewed:  15396 Time(s)

Crystal2.jpg



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Amir Akhavan




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PostPosted: Jan 03, 2010 14:20    Post subject: Re: Scepters - (1)  

That's a funny one.
And one that I understand - if I was a silica molecule, I'd rather look for a sunny new place and start a new crystal on top of the other than to join the terrible green and muddy mess below :-)

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PostPosted: Jan 03, 2010 14:34    Post subject: Re: Scepters - (1)  

I very much like Amir's term "growth inhibition" it very clearly expresses the fact (elaborated by John with his Chinese example) of confined or constrained growth. I would agree that these should not be considered "true" sceptres...just what we need a lead-in to another argument about terminology!
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Luiz Menezes




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PostPosted: Jan 03, 2010 17:51    Post subject: Re: Scepters - (1)  

On my opinion the Brazilian tourmaline scepters are not true scepters, the top has not grown above the lower "stem"; they might have been formed by the etching of the lower part of the prism; the contact between the top and the bottom is never a sharp rhombohedral face or a sharp basal pinacoid but has always a "cathedral-like" pattern typical of etched tourmaline crystals.

On bicolor (pink-green) elbaite crystals from Maxixe mine, Itinga, Minas Gerais, Brazil, found on the late 1990's, several false scepters were manufactured by breaking the thin green cast that was coating the pink bottom of the crystals; on those specimens we could see, looking from the bottom, a very thin hollow zone between the green cast and the pink core, and by breaking this green cast a false scepter was created; therefore, the contact between the top and the "stem" showed conchoidal fracture instead of the "cathedral-like" etched surface that can be seen on the naturally formed tourmaline "scepters" from the 2 classic Brazilian localities (Barra do Salinas and Pederneira).

About other minerals found as scepters, I sold to Daniel Trinchillo on the mid 1990's an outstanding amethyst geode, from Rio Grande do Sul, Brazil, that contained more than 10 calcite scepters, about 5 cm long, unfortunately I don't have a photo of this specimen.

Luiz Menezes
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Jason




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PostPosted: Jan 03, 2010 18:48    Post subject: Re: Scepters - (1)  

good info Luiz..quick question..I thought the maxixe mine was closed in the 70's or 80's and the location lost or something along those lines..I am of course thinking of the beryl..was there also a maxixe tourmaline mine? Is it just a location name used for multiple mines in the area? sorry a little off topic but....is it true that the original maxixe beryl mine is now lost?
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Jordi Fabre
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PostPosted: Jan 04, 2010 03:00    Post subject: Re: Scepters - (1)  

xenolithos wrote:
Peter Megaw wrote:
I very much like Amir's term "growth inhibition" it very clearly expresses the fact (elaborated by John with his Chinese example) of confined or constrained growth. I would agree that these should not be considered "true" sceptres...just what we need a lead-in to another argument about terminology!


Hopefully this won't fuel a terminological 'argument', but I suggest it may help this discussion to distinguish between the use of the term 'scepter' to describe a form (i.e. a stalk with a terminal swelling or knob) and the mode of formation of any particular scepter. This would be consistent with general usage and encompass all the varieties of scepters illustrated above, including the rather suspect mushroom-shaped fluorite scepters from the Erongo in Namibia that have appeared on the market recently. (Unfortunately I don't have a photo of these.) This means that the mode of formation of some scepters is reasonably well understood - growth inhibition, loss of a fragile coat, natural selective etching, deliberate fraudulent etching, etc. Puzzles, as neatly set out by Amir, remain for others, including the classical (or 'true') quartz scepters which started this discussion. Their mode of formation appears to reside in the intricacies of epitaxy. For those unfamiliar with epitaxy, which has been discussed at length in another thread (without consensus) -> http://www.mineral-forum.com/message-board/viewtopic.php?t=429
The Britannica Concise Encyclopedia has a mineralogically useful simple definition: "Process of growing a crystal of a particular orientation on top of another crystal. If both crystals are of the same material, the process is known as homoepitaxy; if the materials are different, it is known as heteroepitaxy" -> http://www.answers.com/topic/epitaxy (link normalized by FMF)
With luck this proposal will obviate an 'argument' about what constitutes a 'true' scepter, and will focus attention on the intriguing puzzles of homoepitaxy.

Duncan

Duncan, if next times you need publish some other link please read this post -> http://www.mineral-forum.com/message-board/viewtopic.php?t=74
Please note that links are permited in FMF to several web pages. Please see this post to know which ones -> http://www.mineral-forum.com/message-board/viewtopic.php?p=5025#5025
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PostPosted: Jan 04, 2010 06:08    Post subject: Re: Scepters - (1)  

I wish that more FMF members were subscribers to Rocks & Minerals. I wrote a column on scepters for the March/April 2003 issue in which I discussed many of the issues now appearing in this thread. I am trying to get the editor, Marie Huizing, to make the column available so that it can be posted here. I have written another column on the origin of scepter-like tourmalines which appeared in the November/December 2002 issue. In this I argue, as does Luiz Menezes, that these are not true scepters.
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Luiz Menezes




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PostPosted: Jan 04, 2010 08:05    Post subject: Re: Scepters - (1)  

amethystguy wrote:
good info Luiz..quick question..I thought the maxixe mine was closed in the 70's or 80's and the location lost or something along those lines..I am of course thinking of the beryl..was there also a maxixe tourmaline mine? Is it just a location name used for multiple mines in the area? sorry a little off topic but....is it true that the original maxixe beryl mine is now lost?

What I know is that this pegmatite belongs to Mineração Arquena, and has been run intermitently; on the past several years it has been operated mostly for the production of petalite for industrial use (special ceramics, not as a lithium ore).

On the past years several pockets of albite with pale purple lepidolite crystals and small pale bicolor elbaite crystals have been found, and it is commom to also find tiny yellow octahedral microlite crystals (up to 5 mm) and micro bipyramidal bown zircon crystals; around 5 years ago some of these specimens also contained tabular grayish-blue beryl crystals attached, these beryl can be considered as "Maxixe beryl", but the quantity was very small (probably less than 10 specimens), and the color was not stable under sunlight.

Luiz
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PostPosted: Jan 04, 2010 09:55    Post subject: Re: Scepters - (1)  

Thanks John and Luiz for your so accurate infos. I already changed the texts in my post -> http://www.mineral-forum.com/message-board/viewtopic.php?p=8959#8959

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Jason




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PostPosted: Jan 04, 2010 10:36    Post subject: Re: Scepters - (1)  

Thanks Luiz..once again some great info! Would like to read that article, John! Was actually thinking of cruising ebay to see about picking up some back issues of Min. Rec. and Rock and Min. for cheap
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Tony L. Potucek




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PostPosted: Jan 06, 2010 17:53    Post subject: Re: Scepters - (1)  

As a further note, I provided Neil Prenn some reversed smoky scepters that I dug from the April Fool vein of Delamar, NV in the early 1970s. The gold mineralization is hosted by Cambrian Prospect Mountain quartzite. I did not find normal scepters in that pocket--pretty strange, in my opinion.

regards, tlp

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Luiz Menezes




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PostPosted: Jan 07, 2010 07:47    Post subject: Re: Scepters - (1)  

Annexed here are photos of some nice true and "false" scepters from my own collection.

All elbaite "false" scepters are natural, I am calling them "false" because they were not formed by the growth of one crystal on the top of another, but by the natural etching of the bottom of a pre-formed crystal.



Scepters 076.jpg
 Description:
Two elbaite "false" scepters - 2.6 x 0.9 cm
Barra do Salinas, Minas Gerais, Brazil
 Viewed:  15032 Time(s)

Scepters 076.jpg



Scepters 063.jpg
 Description:
Tri-color elbaite "false" scepter - 5.4 x 3.7 cm
Barra do Salinas, Minas Gerais, Brazil
 Viewed:  15042 Time(s)

Scepters 063.jpg



Scepters 049.jpg
 Description:
Elbaite "false" scepter - 5.0 x 2.3 cm
Barra do Salinas, Minas Gerais, Brazil
 Viewed:  15047 Time(s)

Scepters 049.jpg



Scepters 017.jpg
 Description:
Smoky quartz scepter - 2.5 x 1.5 cm
Galiléia, Minas Gerais, Brazil
 Viewed:  15062 Time(s)

Scepters 017.jpg



Scepters 034.jpg
 Description:
Smoky quartz/ Amethyst scepter
Felício dos Santos, Minas Gerais, Brazil
 Viewed:  15045 Time(s)

Scepters 034.jpg



Scepters 025.jpg
 Description:
Smoky quartz scepter with slight amethyst shade - 7.5 x 3.0 cm
Santa Maria do Jetibá, Espírito Santo, Brazil
 Viewed:  15044 Time(s)

Scepters 025.jpg



Scepters 020.jpg
 Description:
Smoky quartz scepter, 4.7 x 3.0 cm, with elbaite
Barra do Salinas, Minas Gerais, Brazil
 Viewed:  15043 Time(s)

Scepters 020.jpg



Scepters 043.jpg
 Description:
Smoky quartz scepter, 3 x 1 cm, wih a double terminated elbaite crystal, 3.3 x 0.3 cm
Barra do Salinas, Minas Gerais, Brazil
 Viewed:  15046 Time(s)

Scepters 043.jpg


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Luiz Menezes




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PostPosted: Jan 07, 2010 07:57    Post subject: Re: Scepters - (1)  

Hi Amethystguy, this is a photo of a natural bicolor elbaite "false" scepter, with an attached microlite crystal, from Maxixe mine, found in the big pocket on the late 1990's.


Scepters 067.jpg
 Description:
Bicolor elbaite "false" scepter, 5.2 x 1.5 cm, with a microlite crystal, 4 mm
Maxixe mine, Itinga, Minas Gerais, Brazil
 Viewed:  15031 Time(s)

Scepters 067.jpg


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vic rzonca




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PostPosted: Jan 07, 2010 09:13    Post subject: Re: Scepters - (1)  

Luiz, when found in-situ, is the etched tourmaline's c axis perpendicular to the horizontal or can it even be determined?
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Luiz Menezes




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PostPosted: Jan 07, 2010 09:28    Post subject: Re: Scepters - (1)  

Vic, I have no idea, I have never withnessed the digging of a pocket containing tourmaline scepters.

Luiz
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PostPosted: Jan 07, 2010 09:56    Post subject: Re: Scepters - (1)  

Luiz

I am really grateful for your input. Perhaps the term false scepter will be generally adopted. This was also the substance of my article in R&M which the new owner of the magazine will not allow me to post here.

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PostPosted: Jan 07, 2010 12:37    Post subject: Re: Scepters - (1)  

nice pics luiz..well done..you have some nice specs. Does no one have any pics of a spec. from hallelujah junction? figured someone would....as ..sigh..I do not
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PostPosted: Jan 27, 2010 22:28    Post subject: Re: Scepters - (1)  

This is the closest thing to an amethyst scepter I have from Diamond Hill, SC.


IMG_3569.JPG
 Description:
Please excuse the bad photo.
personally collected
15 x 9 x 4 cm
 Viewed:  14772 Time(s)

IMG_3569.JPG



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PostPosted: Feb 08, 2010 22:04    Post subject: Re: Scepters - (1)  

My friend found this crystal in Cary, NC. We have been debating if this is a scepter or not. It does seem to have the scepter shape although if it is then it is very subtle. Please review these photos. I am very interested in your opinions and ideas concerning this crystal. Thank you.


IMG_4017.JPG
 Description:
Cary, NC
14 x 8.5 x 6.5 cm
 Viewed:  14660 Time(s)

IMG_4017.JPG



IMG_4020.JPG
 Description:
Cary, NC
14 x 8.5 x 6.5 cm
 Viewed:  14651 Time(s)

IMG_4020.JPG



IMG_4036.JPG
 Description:
Cary, NC
14 x 8.5 x 6.5 cm
 Viewed:  14648 Time(s)

IMG_4036.JPG



IMG_4044.JPG
 Description:
Cary, NC
14 x 8.5 x 6.5 cm
 Viewed:  14653 Time(s)

IMG_4044.JPG



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