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23 Feb-20:50:19 Re: gail spann's tucson adventures. February 2018. (Gail)
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23 Feb-19:54:00 Re: gail spann's tucson adventures. February 2018. (Kevin Schofield)
23 Feb-19:46:03 Re: gail spann's tucson adventures. February 2018. (Gail)
23 Feb-19:38:41 Re: gail spann's tucson adventures. February 2018. (Gail)
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23 Feb-19:23:54 Re: gail spann's tucson adventures. February 2018. (Gail)
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23 Feb-18:57:45 Re: gail spann's tucson adventures. February 2018. (Gail)
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23 Feb-17:56:26 Re: gail spann's tucson adventures. February 2018. (Gail)
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  Topic: Faden Quartz Crystals - (26)
marco campos-venuti

Replies: 48
Views: 16863

PostForum: Featured Columns of FMF   Posted: Dec 15, 2017 11:28   Subject: Re: Faden Quartz Crystals - (26)
Hi Roger,
I consider we are at the same side of the theories, as anti-official. But something in your discussion sounds strange to me.
A gel is a solid and for that reason can't have viscosity that ...
  Topic: Information about a Rhodochrosite specimen
marco campos-venuti

Replies: 3
Views: 1067

PostForum: Minerals and Mineralogy   Posted: Nov 18, 2017 09:16   Subject: Re: Information about a Rhodochrosite specimen
Check mindat:
https://www.mindat.org/photo-519101.html
Wutong Mine (Wudong Mine), Liubao, Cangwu Co., Wuzhou Prefecture, Guangxi Zhuang Autonomous Region, China
  Topic: Assistance in getting locality info for this Mexican? orthoclase & amphibole specimen
marco campos-venuti

Replies: 4
Views: 839

PostForum: What is it? - Where is it from?   Posted: Nov 18, 2017 06:31   Subject: Re: Assistance in getting locality info for this Mexican? orthoclase & amphibole speci
I found a specimen in mindat from Durango with very similar appearance, labeled orthoclase with horneblende. Photo is by Rock Currier and specimen is from the collection of Miguel Romero.
mindat.org/ ...
  Topic: Micro photos of inclusions in Quartz
marco campos-venuti

Replies: 50
Views: 8650

PostForum: Micros & Macros - Images of Minerals   Posted: Nov 14, 2017 06:50   Subject: Re: Micro photos of inclusions in Quartz
I have one sample of the blue inclusion. I'm not sure it is natural or synthetic quartz. No info about any deposit.
  Topic: Super thin hematite inclusions in amethyst
marco campos-venuti

Replies: 22
Views: 3111

PostForum: Micros & Macros - Images of Minerals   Posted: Nov 13, 2017 04:21   Subject: Re: Super thin hematite inclusions in amethyst
It is from Rome!
(We are joking, come back to the topic please)
  Topic: Super thin hematite inclusions in amethyst
marco campos-venuti

Replies: 22
Views: 3111

PostForum: Micros & Macros - Images of Minerals   Posted: Nov 12, 2017 12:44   Subject: Re: Super thin hematite inclusions in amethyst
And here is what we call Quartz with iron oxides, because we don't know what it really is. Also from Minas Gerais
  Topic: Super thin hematite inclusions in amethyst
marco campos-venuti

Replies: 22
Views: 3111

PostForum: Micros & Macros - Images of Minerals   Posted: Nov 12, 2017 12:41   Subject: Re: Super thin hematite inclusions in amethyst
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 l ...
  Topic: Super thin hematite inclusions in amethyst
marco campos-venuti

Replies: 22
Views: 3111

PostForum: Micros & Macros - Images of Minerals   Posted: Nov 12, 2017 12:31   Subject: Re: Super thin hematite inclusions in amethyst
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 woul ...
  Topic: Super thin hematite inclusions in amethyst
marco campos-venuti

Replies: 22
Views: 3111

PostForum: Micros & Macros - Images of Minerals   Posted: Nov 12, 2017 12:18   Subject: Re: Super thin hematite inclusions in amethyst
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 confusio ...
  Topic: Question about Sphalerite from Spain?
marco campos-venuti

Replies: 11
Views: 1618

PostForum: What is it? - Where is it from?   Posted: Nov 09, 2017 04:03   Subject: Re: question about Sphalerite from Spain
Doesn't looks Spanish. Small and numerous crystals, very dark and slightly elongated shape.
  Topic: Rarest quartz twins with inclined axes C
marco campos-venuti

Replies: 38
Views: 5577

PostForum: Minerals and Mineralogy   Posted: Nov 08, 2017 20:27   Subject: Re: Rarest quartz twins with inclined axes C
I think auto-epitaxy is a synonym of twinning. Epitaxy is between two different minerals.
If a secondary xl (or a epitaxial film) grows over a main xl, its atoms will continue the lattice of the firs ...
  Topic: Rarest quartz twins with inclined axes C
marco campos-venuti

Replies: 38
Views: 5577

PostForum: Minerals and Mineralogy   Posted: Nov 08, 2017 19:25   Subject: Re: Rarest quartz twins with inclined axes C
I mean that often it can be a twin instead of an accident.
  Topic: Rarest quartz twins with inclined axes C
marco campos-venuti

Replies: 38
Views: 5577

PostForum: Minerals and Mineralogy   Posted: Nov 08, 2017 15:33   Subject: Re: Rarest quartz twins with inclined axes C
John, I think that when two crystals grow over a matrix, many different forces interact. In contrary, when a second crystal grows over a face of a first crystal, its orientation depends mainly by atom ...
  Topic: Fluorite habit
marco campos-venuti

Replies: 5
Views: 1356

PostForum: Minerals and Mineralogy   Posted: Nov 04, 2017 19:06   Subject: Re: Fluorite habit
It looks as a purple cube with a clear interior. The two faces are cleavage faces showing the interior of the crystal, cutting two vertex of the cube.
  Topic: One of a kind
marco campos-venuti

Replies: 9
Views: 1265

PostForum: What is it? - Where is it from?   Posted: Oct 30, 2017 02:49   Subject: Re: One of a kind
Wow! A message in a stone!
Despite its incredible unusual text, this stone is a piece of a septaria, common near Glenn or South Haven, MI. Also called Lighting Stones, they are concretions of devonia ...
  Topic: Rarest quartz twins with inclined axes C
marco campos-venuti

Replies: 38
Views: 5577

PostForum: Minerals and Mineralogy   Posted: Oct 23, 2017 15:39   Subject: Re: Rarest quartz twins with inclined axes C
The prism of both crystals has a face parallel to the picture.
The crystal B is rotated 50 degrees in respect with A, that is the same angle between the prism and the rhombohedron, resulting that the ...
  Topic: Scepters - (1)
marco campos-venuti

Replies: 78
Views: 69174

PostForum: Featured Columns of FMF   Posted: Oct 23, 2017 13:26   Subject: Re: Scepters - (1)
Some more specimens.
  Topic: Rarest quartz twins with inclined axes C
marco campos-venuti

Replies: 38
Views: 5577

PostForum: Minerals and Mineralogy   Posted: Oct 23, 2017 13:05   Subject: Re: Rarest quartz twins with inclined axes C
Hi, I have a strange group of crystals of irradiated quartz from Arkansas.
The crystal A lays on the matrix. The crystal B grows from a rhombohedron face of crystal A. A and B crystals share a plane ...
  Topic: Mineralogical Museum Luigi Celleri (MUM) of San Piero in Campo in Elba Island, Italy
marco campos-venuti

Replies: 5
Views: 1660

PostForum: Worlwide Museums & Visits to Museums and private collections   Posted: Oct 20, 2017 11:37   Subject: Re: Mineralogical Museum Luigi Celleri (MUM) of San Piero in Campo in Elba Island, Italy
I just want to add the photo of the man to whom the museum is dedicated: Luigi Celleri (San Piero in Campo, 6- 5-1828, San Piero in Campo, 4-21-1900) . A real rockhound.
  Topic: Weird face in quartz
marco campos-venuti

Replies: 21
Views: 7239

PostForum: Minerals and Mineralogy   Posted: Oct 20, 2017 11:20   Subject: Re: Weird face in quartz
Hi Reef, do you think these faces are originated by dissolution (etching)? They remember the "Quarzi Gommoidi" of Luigi Bombicci from Colle Palombaia, Elba Island. He refers to a finding of ...
 
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