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Jim Prentiss
Joined: 01 Dec 2009
Posts: 103
Location: Ohio
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 Posted: May 10, 2010 08:01 Post subject: Re: Calcite Forms - (4) |
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Hello everyone,
Well I like this type of thread. It allows everyone to see numerous examples of a certain species. I can't wait for the next one.
I have to add one of my personal favorites. Also I am looking for some clarification. I have seen and heard this specimen described as both nailhead spar and poker chip crystal aggregates. What say Ye?
See ya later,
jimp
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| This if from Yaogangxian Mine, Chenzhou Prefecture, Hunan Province, China. the specimen is about 2 3/4" (7 cm) in diameter |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4894
Location: Barcelona
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| Posted: May 10, 2010 08:35 Post subject: Re: Calcite Forms - (4) |
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China? You said China? ;-)
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A transparent, discoidal, twinned, crystal of Calcite and with Stibnite
Xikuangshan Mine, Lengshuijiang, Hunan, China
Mined in 2009
Specimen size: 4.9 × 3.1 × 1.4 cm.
Main crystal size: 2.8 × 2.6 cm.
Minor fluorescence short UV
Photo: Reference Specimens -> http://www.fabreminerals.com/specimens/RSCN-china-notable-specimens.php#EH6P5 |
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Jim Prentiss
Joined: 01 Dec 2009
Posts: 103
Location: Ohio
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| Posted: May 10, 2010 09:16 Post subject: Re: Calcite Forms - (4) |
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Hello Jordi,
Incredible piece, Do you call this one Excalibur?
jimp
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Jason
Joined: 31 Dec 2008
Posts: 254
Location: atlanta
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| Posted: May 10, 2010 10:00 Post subject: Re: Calcite Forms - (4) |
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calcite + stibnite
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4894
Location: Barcelona
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| Posted: May 10, 2010 10:05 Post subject: Re: Calcite Forms - (4) |
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| Jim Prentiss wrote: | | Do you call this one Excalibur? |
The Punchinello! ;-)
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: May 10, 2010 13:35 Post subject: Re: Calcite Forms - (4) |
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Jim:
I don't think it necessary to come up with a name for every habit. In my view your calcite is neither nailhead nor pokerchip.
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John S. White
aka Rondinaire |
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Jim Prentiss
Joined: 01 Dec 2009
Posts: 103
Location: Ohio
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| Posted: May 10, 2010 14:57 Post subject: Re: Calcite Forms - (4) |
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Hello John,
PT Barnum and the great egress, right?
Would something less exotic be the way to go, such as bladed?
Thanks,
Jim Prentiss
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ruggyh
Joined: 10 May 2010
Posts: 6
Location: Morgan Hill, California
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| Posted: May 10, 2010 16:04 Post subject: Re: Calcite Forms - (4) |
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Fish tail twin, with Stibnite , Xikaungshan deposit, Hunan Province, China
calcite 35x30x16 mm
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Carles Millan
Site Admin
Joined: 05 May 2007
Posts: 1469
Location: Catalonia
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| Posted: May 10, 2010 16:39 Post subject: Re: Calcite Forms - (4) |
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Calcite, stibnite
Stibnite crystals on a calcite lenticular crystal. Overall size: 125 mm x 47 mm. Calcite crystal: 47 mm wide.
Xikuangshan Sb deposit, Lengshuijiang, Loudi, Hunan, China.
Photos copyright © Carles Millan. Reproduction allowed as long as the author's name is cited. Creative Commons Attribution License - Some Rights Reserved.
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: May 11, 2010 06:43 Post subject: Re: Calcite Forms - (4) |
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Just to keep this going with Jim, I don't think that bladed works either. Bladed puts me in mind of a blade of grass or a sword blade. You know that anyone is perfectly free to coin their own habit names. What if we described your calcite as illustrating the "prentiss habit"?
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John S. White
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Jim Prentiss
Joined: 01 Dec 2009
Posts: 103
Location: Ohio
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| Posted: May 11, 2010 09:15 Post subject: Re: Calcite Forms - (4) |
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Why, thank you John,
I always wanted some sort of noteriety. Do you think I would gain points in a competitive display with that? I would like to coin a few terms of my own. Borrowing from my profession, maybe I could reference turbine rotor diaphragm or main rotor hub fairing, in some way. Or throw out all convention and use their respective part numbers instead. This Calcite is a 23053723 habit or a 369D21202 crystall aggregate.
I have seen many different descriptions of habit in various references, and what I have found is that many of them have the same descriptions for habit but then have a few that the other books do not. I suppose the safest bet would be to go with what all the authors agree upon. What do you think on that?
As far as "poker chip" habit, the only places I recall seeing that is on dealer web sites. A sales ploy? As to nail head; I read in one book that Nail Head Spar is a "composite variety having the form suggested by the name". My question here then would it also include the stem of the nail to be considered "Nail Head"?
What, then, would be an apprpriate, generally acceptable description of my Calcite?
Well this should do for now. This is actually my second writing as the first disappeared in the black hole a while ago.
Thanks again John,
Jim Prentiss
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: May 11, 2010 12:23 Post subject: Re: Calcite Forms - (4) |
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How about "artichoke calcite"? It more closely resembles an artichoke than does "artichoke quartz."
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John S. White
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Jim Prentiss
Joined: 01 Dec 2009
Posts: 103
Location: Ohio
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| Posted: May 12, 2010 19:50 Post subject: Re: Calcite Forms - (4) |
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Hi John,
Artichoke it is. I have amended my mineral glossary.
Thanks,
Jim
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: May 13, 2010 08:15 Post subject: Re: Calcite Forms - (4) |
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Here is one of the same type that I have, a calcite with stibnite from the Xikuangshan mine, China, 4.5 cm across.
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Pete Richards
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Joined: 29 Dec 2008
Posts: 828
Location: Northeast Ohio
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| Posted: May 13, 2010 09:08 Post subject: Re: Calcite Forms - (4) |
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| Jim Prentiss wrote: |
I have to add one of my personal favorites. Also I am looking for some clarification. I have seen and heard this specimen described as both nailhead spar and poker chip crystal aggregates. What say Ye?
jimp |
I take "nailhead" to refer to a shallow rhombohedral habit - three faces on top and three on bottom, the width substantially greater than the height. The name comes from the old hand-made nails which often had three (or four) facets on the head made by the blows from the blacksmith's hammer. And the name only refers to the head of the nail - after all it's "nailhead spar" not "nail spar".
I take "pokerchip" to refer to a thin tabular habit with one flat pinacoidal face on top and one on the bottom. I think Charcas is a locality for such crystals.
That said, I agree with John that such names for habits are not always helpful and are not necessary. They are not precisely defined; in fact it is often difficult to find any definition of them, precise or otherwise. They may be highly descriptive of a certain habit to the person who originates them, but may suggest a different form to someone else in another place or time.
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Collecting and studying crystals with interesting habits, twinning, and epitaxy |
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: May 13, 2010 10:31 Post subject: Re: Calcite Forms - (4) |
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Wonderful poker chip calcites have been coming out of China over the last several years, many of which appear twinned and show beautiful zoning from colorless transparent to white or gray. I believe Jordi has at least one very good image.
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John S. White
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4894
Location: Barcelona
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| Posted: May 13, 2010 11:22 Post subject: Re: Calcite Forms - (4) |
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Maybe this one?
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Twinned Calcite
Wuzhou Mine, Guangxi, China |
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26035 Time(s) |
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: May 13, 2010 18:58 Post subject: Re: Calcite Forms - (4) |
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Jordi:
That was not exactly what I had in mind. I will try to get a photo of one that I have.
Thanks for posting this one.
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John S. White
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Jim Prentiss
Joined: 01 Dec 2009
Posts: 103
Location: Ohio
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| Posted: May 13, 2010 21:20 Post subject: Re: Calcite Forms - (4) |
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Hello all,
These are all nice pieces. Like I said earlier, I like this kind of post as it creates a place for numerous examples of a particular species to be shown. Like a publication on one mineral.
Jim Prentiss
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ruggyh
Joined: 10 May 2010
Posts: 6
Location: Morgan Hill, California
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| Posted: May 13, 2010 22:52 Post subject: Re: Calcite Forms - (4) |
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Calcite scalenohedron (dog tooth) on Stibnite with Fluorite
Xikaungshan deposit, Hunan Province, China
Calcite crystal 30mm x 14mm
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25939 Time(s) |
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