We use cookies to show content based on your preferences. If you continue to browse you accept their use and installation. More information. >

FMF - Friends of Minerals Forum, discussion and message board
The place to share your mineralogical experiences


Spanish message board






Newest topics and users posts
28 Mar-09:37:50 Re: 2 unknowns co-occurring with caledonite, grand reef mine, az (Cfrench58)
27 Mar-19:47:08 Re: 2 unknowns co-occurring with caledonite, grand reef mine, az (Pete Richards)
27 Mar-16:15:44 Re: 2 unknowns co-occurring with caledonite, grand reef mine, az (Cfrench58)
27 Mar-15:18:59 Re: 2 unknowns co-occurring with caledonite, grand reef mine, az (Alfredo)
27 Mar-14:39:29 2 unknowns co-occurring with caledonite, grand reef mine, az (Cfrench58)
27 Mar-05:21:48 Re: the mim museum in beirut, lebanon (Mim Museum)
27 Mar-05:03:26 Re: trying to find information on rose/pink quartz and tourmaline associations. (Ning)
27 Mar-02:39:50 Re: the mim museum in beirut, lebanon (Tobi)
27 Mar-00:23:28 Re: collection of volkmar stingl (Volkmar Stingl)
26 Mar-00:53:41 Re: collection of volkmar stingl (Volkmar Stingl)
25 Mar-13:32:10 Re: collection of michael shaw (Michael Shaw)
25 Mar-00:25:58 The mizunaka collection - quartz (Am Mizunaka)
23 Mar-13:35:22 Re: collection of firmo espinar (Firmo Espinar)
22 Mar-08:32:28 Re: collection of michael shaw (Michael Shaw)
22 Mar-04:20:41 Re: the mim museum in beirut, lebanon (Mim Museum)
21 Mar-22:49:19 Re: green seam. Looks like it in a state of decay. (Ning)
21 Mar-22:47:40 Re: green seam. Looks like it in a state of decay. (Ning)
21 Mar-22:45:25 Re: green seam. Looks like it in a state of decay. (Ning)
21 Mar-15:34:23 Re: the mizunaka collection - quartz (Am Mizunaka)
21 Mar-14:35:08 Re: jim’s mineral collection (Jim Wilkinson)
21 Mar-14:15:36 The 4th phoenix heritage mineral show (phms) hosted by mineralogical society of arizona (m (Chris Whitney-smith)
21 Mar-04:36:10 Re: the mizunaka collection (Tobi)
21 Mar-04:11:47 Re: jim’s mineral collection (James Catmur)
20 Mar-23:34:15 The mizunaka collection - quartz (Am Mizunaka)
20 Mar-18:13:16 Re: jim’s mineral collection (Jim Wilkinson)

For lists of newest topics and postings click here


RSS RSS

View unanswered posts

Why and how to register

Index Index
 FAQFAQ RegisterRegister  Log inLog in
 {Forgotten your password?}Forgotten your password?  

Like
111802


The time now is Mar 28, 2024 14:23

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
The information provided within this Forum about localities is only given to allow reference to them. Any visit to any of the localities requires you to obtain full permission and relevant information prior to your visit. FMF is strictly against any illicit activities related to collecting minerals.
Endomorph or Pseudomorph?
  Goto page Previous  1, 2, 3  Next
  Index -> The Ten Thousand Club
Like
4


View previous topic :: View next topic  
Author Message

Aymeric




Joined: 20 Feb 2009
Posts: 32
Location: Between France & Pakistan

View user's profile

Send private message

PostPosted: Feb 20, 2009 17:19    Post subject: Re: Endomorph or Pseudomorph?  

Excellent reading, thank you very much Mark ! I'm regularly confronted to what I used to call pseudomorphs, and know I see them under a new light ! aaaaah, the pleasure of learning !
Back to top
Reply to topic Reply with quote
Like
   

Pete Richards
Site Admin



Joined: 29 Dec 2008
Posts: 828
Location: Northeast Ohio


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Feb 20, 2009 19:27    Post subject: Re: Endomorph or Pseudomorph?  

I agree with Mark that the use of pseudomorph as a general term is useful. I had never heard of endomorph before, and to my thinking it does not make any sense. If the original mineral is inside (endo) it has not morphed! I could see using the term endomorph for a cast as Mark defines it, but I think the number of situations where it could be applied unambiguously is pretty small. You would have to determine that an epimorph was cast with a new mineral and dissolved away leaving an "endomorph" in this sense, AND that this was the process instead of simple replacement pseudomorphy. Not likely.

Incidentally, the terms mold and cast are in common usage in paleontology. The mold is what is left when the fossil dissolves away and the matrix retains the shape, and a cast is what results when the hollow space is filled in with another mineral.

An interesting cross-discipline experiment: take a nice brachiopod fossil and immerse it in a concentrated solution of copper sulfate. After a week or so, you'll have a brachiopod made at least in part of malachite - a pseudomorph of malachite after brachiopod!

_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 961
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 26, 2010 13:55    Post subject: Re: Endomorph or Pseudomorph?  

Here is a beautiful example of development of an epimorph/encrustation pseudomorph from the famous "crazy lace" agate locality in Chihuahua. We have an exploration project called "Cinco de Mayo" surrounding the locale...and it appears genetically related to the Au-Ag-Pb-Zn-Cu-Mo mineralization we're chasing, so we've had rare justification for paying close attention to it. I have always been fascinated by the patterns in crazy lace...sharp rectilinear banding mixed with wild arcuate banding...but frustrated by only having standard 30 x 40 oval cabochon samples to study.

In examining outcrops of the agate it became apparent that the agate filled voids in a limestone breccia developed along a complex thrust fault. The breccia clearly ruptured repeatedly and voids were alternately filled with fine-grained laminated sediments (cave fill) and scalenohedral calcite with silicification occurring repeatedly. The patterns of the "ghosts" of the scalenohedral calcites suggested fillings remarkably similar to the "diente de perro" (dog-tooth) calcite that cements limestone breccias at Santa Eulalia, which helped in understanding what is going on. It was easy to find hand-samples of silicified cave fill showing beautiful cross-bedding, the difficulty was to get a manageable size piece that showed the dog-teeth unequivocally. I finally succeeded recently in getting couple of slabs of just such a piece and am delighted with the results Here are three increasing close-up scans that show what happened and demonstrate how this epimorph developed.

It clearly looks like scalenohedral calcite was first coated with something...now silica, and then the body of the crystal dissolved away leaving "voids" above and below the "crust" into which beautifully banded chalcedony could grow In essence an "endomorph" that lost its "morph" leaving just a delicate "endo". (Being an ex-physical anthropologist ectomorph en route to becoming a mesomorph, I think this term should be abandoned in favor of epimorph...but I am not trying to stir the semantic pot here).

Note that the growth bands work both ways off the coating, suggesting that it was somehow supported...probably in silica gel. If you look very closely you can see that there were crystallites of something elongate...and silica tubules as well...that also grew in both directions off the crust. These appear to have had more 'elbow-room" to grow off the original free faces of the calcite however suggesting that things were more liquid in that direction. Notably the banding is not symmetrical with respect to the crust, perhaps indicating it remained a barrier to gel or fluid movement across the void. It also looks like the red iron-oxide coloring was introduced late along the "veinlet" that cuts across the banding.

Looking at more chaotic banding iin many crazy lace agates I suspect that in many cases the crust collapsed and formed piles of shards that then got overgrown by the agate stage...and cutting through these at various angles gives the wild patterns the material is famous for.

Happy to hear agate and pseudomorph experts weigh in on this!!!



crazy lace w.jpg
 Description:
Crazy lace agate slab about 16 cm across
 Viewed:  36713 Time(s)

crazy lace w.jpg



crazy lace CU w.jpg
 Description:
Close-up view of crazy lace agate...field of view about 6 cm
 Viewed:  36679 Time(s)

crazy lace CU w.jpg



crazy lace CCU w.jpg
 Description:
Closest-up view of crazy lace agate...field of view about 4 cm
 Viewed:  36677 Time(s)

crazy lace CCU w.jpg



_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

Tomasz Praszkier




Joined: 20 Dec 2009
Posts: 93
Location: Warszawa


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 26, 2010 14:46    Post subject: Re: Endomorph or Pseudomorph?  

Mark,

My English is poor but... Did I well understood that in your opinion perimorphose=epimorphose?? For this kind of coatings with dissoluted primary mineral I always used term perimorphose.

Tom

_________________
Tomek
Back to top
Reply to topic Reply with quote
Like
   

Pete Richards
Site Admin



Joined: 29 Dec 2008
Posts: 828
Location: Northeast Ohio


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 26, 2010 18:18    Post subject: Re: Endomorph or Pseudomorph?  

Peter,

Certainly these are very interesting images. Could you please put the specimen through a tomograph and show us the slices perpendicular to this viewing direction? That would be very helpful in deciding whether the original mineral was calcite. But it might require a four-dimensional tomograph with retroactive capability, and not many labs have that....

Cheers

_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 961
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 26, 2010 18:29    Post subject: Re: Endomorph or Pseudomorph?  

Pete, tongue-in-cheek aside, the surface outcrops of these do give a 3D view and they are symmetrical with respect to the axis of elongation...but I suspect you would only be convinced of calcite if I ran it through a dual-channel reframitizer with proactive processing and at the moment that senstive piece of equipment has burned out another filament...
_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

Antonio Da Silveira




Joined: 11 Oct 2007
Posts: 25
Location: Artigas

View user's profile

Send private message

PostPosted: Jan 26, 2010 18:59    Post subject: Re: Endomorph or Pseudomorph?  

Amethyst Pseudomorph, Artigas Uruguay.

Antonio



Pseudomorph2.JPG
 Description:
Amethyst Pseudomorph tall 28 cm
"Santiño Mine"
 Viewed:  36647 Time(s)

Pseudomorph2.JPG



Pseudomorph.JPG
 Description:
Amethyst Santiño Mine, Uruguay
 Viewed:  36666 Time(s)

Pseudomorph.JPG



Pseudomorph1.JPG
 Description:
Amethyst Santiño Mine
 Viewed:  36625 Time(s)

Pseudomorph1.JPG


Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 4888
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 27, 2010 03:17    Post subject: Re: Endomorph or Pseudomorph?  

Tomasz Praszkier wrote:
... Did I well understood that in your opinion perimorphose=epimorphose??...

Is another interesting thread related with this topic -> https://www.mineral-forum.com/message-board/viewtopic.php?t=299
Back to top
Reply to topic Reply with quote
Like
   

John S. White
Site Admin



Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 27, 2010 05:49    Post subject: Re: Endomorph or Pseudomorph?  

Antonio:

I have seen several very similar specimens recently from Artigas. They are magnificent and they defy understanding. Talk about multi-stage paragenesis, there must have been at least a half-dozen events in the development of this amazing specimen.

_________________
John S. White
aka Rondinaire
Back to top
Reply to topic Reply with quote
Like
   

John S. White
Site Admin



Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 27, 2010 05:54    Post subject: Re: Endomorph or Pseudomorph?  

Peter, why are you still working with that obselete hardware? It is about time that you upgraded to newer technologies. (I really dislike technologies instead of technology, but it is very much in fashion these days and I use it here only because it seems to fit the sense of this thread.)
_________________
John S. White
aka Rondinaire
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 961
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 27, 2010 23:00    Post subject: Re: Endomorph or Pseudomorph?  

John...never thought I'd live to hear you admit to being a slave of fashion! I love it!
_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 961
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Feb 20, 2010 19:47    Post subject: Re: Endomorph or Pseudomorph?  

Here's a puzzler I picked up at Tucson last week that plays to some recent discussions we've had regarding various mechanisms of pseudomorphing. This material has been around in many forms from Guanajuato for years...but generally as hollow shells of dolomite with the shape of precursor calcite that is gone. This one is different in that calcite is still there in the center with perfectly mirror smooth faces...and there is a void between the calcite and the dolomite shell. The interior-looking surface of the dolomite is crystallized, but not smooth, and tiny pyrites grew on both the smooth calcite faces and the interior dolomite face. Did the calcite grow inside the shell after an earlier calcite stage that was directly coated by dolomite was dissolved? or was the calcite covered with something that got covered by dolomite and was itself then dissolved. This would make the dolomite an epimorph after something other than calcite that itself took the shape of the calcite but is now gone. The pyrites add another dimension, they are clearly younger than both the calcite and dolomite shell, but did they grow in the void after the absent mystery phase got dissolved, or did they grow in it? It has been suggested that ephemeral phases of halite or gypsum/anhydrite...or even gels can grow between epithermal mineralization stages and later get removed leaving no trace.

Any thoughts of other possibilities, or other phases that might form and disappear into solutions that damage neither calcite nor dolomite?



Calcite GTO 013.jpg
 Description:
dolomite over calcite "epimorph" from Guanajuato, Mexico. Minature
 Viewed:  36216 Time(s)

Calcite GTO 013.jpg



Calcite GTO 022.jpg
 Description:
close up showing void between dolomite overgrowth and smooth calcite foundation crystal
 Viewed:  36243 Time(s)

Calcite GTO 022.jpg



Calcite GTO 014.jpg
 Description:
close up of pyrite crystals on smooth calcite crystal face in void under dolomite
 Viewed:  36205 Time(s)

Calcite GTO 014.jpg



_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

dtkasper




Joined: 27 Dec 2010
Posts: 13
Location: Lancaster

View user's profile

Send private message

PostPosted: Dec 27, 2010 04:17    Post subject: Re: Endomorph or Pseudomorph?  

Neither.
The main band looks like a hash of zeolite, perhaps natrolite. They make the short rods with rounded tips. Then calcite formed on top of the hash. It encased most of the natrolite, but not all. Then silica intruded. The pink may, in fact, be from other related zeolites such as heulandite. Silica as chalcedony and agate has a strong propensity to precipitate in carbonate systems. In this case the silica precipitated in a limestone body. It is a vein deposit, so deposition was occurring inward from both sides at the same time. The center with the zeolites and calcite was the last open space before the final silica intrusion. The one-sided nature of the crystallization shows that this vein was probably far from vertical and the crystals are a geopetal indicating the original bottom of the formation. Vertical veins would be expected to have the mineralization pointed to the center from both sides, top and bottom of your specimen in this case.
Back to top
Reply to topic Reply with quote
Like
   

dtkasper




Joined: 27 Dec 2010
Posts: 13
Location: Lancaster

View user's profile

Send private message

PostPosted: Dec 27, 2010 04:33    Post subject: Re: Endomorph or Pseudomorph?  

Neither.
The solution had two phases. The dolomite formed first and the calcite was entrapped second. The pyrite created some acidity leading to the dissolution of the calcite.

An equivalent with amygdules is found all the time. The amygdules are silica found with calcite rhombs in them and the only explanation people propose is meteoric waters intruding with calcite afterward. Of course, their are molds of calcite crystals on the outsides and insides of amygdules all the time. I say it came from one colloid and the crystallization favors silica precipitation first. The water is pushed up and out with the calcite. You get a blister on top commonly with calcite or druzy quartz.

Extrapolations across geologic systems has to be done carefully, but I see the common equivalence of silica and calcite all the time. Calcite forms at the very first and at the very end, two times and for different reasons (first insolubility at high temp, second degassing of CO2 at low temp) so the sequence of formation is always complex to unravel.
Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 4888
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Dec 27, 2010 04:46    Post subject: Re: Endomorph or Pseudomorph?  

Hi Kasper, welcome to FMF!

BTW, could you help Elise here? -> https://www.mineral-forum.com/message-board/viewtopic.php?t=1461
Back to top
Reply to topic Reply with quote
Like
   

vic rzonca




Joined: 18 Nov 2008
Posts: 820
Location: MA


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 07, 2011 11:24    Post subject: Re: Endomorph or Pseudomorph?  

I must leave the extrapolations to others,(I am but a humble carpenter) Here are my two cents. Would it be called a quartz perimorph of calcite?


IMG_2002.JPG
 Description:
Looking into the cavity left by calcite.
 Viewed:  34932 Time(s)

IMG_2002.JPG



IMG_2004.JPG
 Description:
7x2 cm. quartz from Sakur, Maharashtra, India.
 Viewed:  34930 Time(s)

IMG_2004.JPG


Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 961
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 07, 2011 12:18    Post subject: Re: Endomorph or Pseudomorph?  

Vic...I started out as a carpenter too...and I seem to remember there was a least one other humble carpenter who created a stir in his time?

If the shell is smooth on the inside this would suggest the quartz/chalcedony/silica gel coated the calcite and then built up layers farther outboard...this would make it an endomorph. The calcite probably dissolved as the temperature dropped given calcite's retrograde solubility.

If the shell is not smooth on the inside and there is evidence that the quartz actually replaced the calcite...perhaps along fractures or cleavage planes then it would be a (partial) replacement pseudomorph.

This would be a tougher call if banded quartz/chalcedony filled the core as well...it would be hard to tell if it did so after the calcite was dissolved or at the expense of the calcite. The crazylace agates of Chihuahua raise this question.



crazy lace CCU.jpg
 Description:
Slab of crazy lace cut parallel to c-axis of earlier calcite. Note difference in banding patterns across what was obviously the outer surface of the calcite...suggesting there was filling of a void where calcite was removed on one side and layered build up on the other
 Viewed:  34932 Time(s)

crazy lace CCU.jpg



_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

vic rzonca




Joined: 18 Nov 2008
Posts: 820
Location: MA


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 07, 2011 12:57    Post subject: Re: Endomorph or Pseudomorph?  

Carpentry's changed a lot since then, Pete. (I don't mean when you where in it)

On close examination of your agate, is there a live edge ( a woodworkers term for the original outer layer of a stem or trunk) or a visible starting plane where quartz nucleation began on the calcite face? Not sure if I'm being clear.
Back to top
Reply to topic Reply with quote
Like
   

Peter Megaw
Site Admin



Joined: 13 Jan 2007
Posts: 961
Location: Tucson, Arizona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 07, 2011 13:09    Post subject: Re: Endomorph or Pseudomorph?  

I used a hammer and hand-saw...fairly ancient and unchanged technology.

Yes there is a live edge...you can see it right under the dark iron-stained layer

_________________
Siempre Adelante!
Back to top
Reply to topic Reply with quote
Like
   

vic rzonca




Joined: 18 Nov 2008
Posts: 820
Location: MA


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 07, 2011 13:32    Post subject: Re: Endomorph or Pseudomorph?  

Nail guns , laser levels and sliding compound miter boxes, my infirmities insist.
Thanks Pete, very clear. Quite a study of process and sequence.
Back to top
Reply to topic Reply with quote
Like
   
Display posts from previous:   
   Index -> The Ten Thousand Club   All times are GMT - 5 Hours
Page 2 of 3
  Goto page Previous  1, 2, 3  Next  

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


All pictures, text, design © Forum FMF 2006-2024


Powered by FMF