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Newest topics and users posts
01 Jun-11:16:03 Re: collection of firmo espinar (Firmo Espinar)
01 Jun-06:27:15 Re: any interesting minerals from ukraine? (David)
01 Jun-06:03:02 Re: any interesting minerals from ukraine? (David)
01 Jun-04:01:30 Re: any interesting minerals from ukraine? (Peter Lemkin)
01 Jun-03:34:37 Re: any interesting minerals from ukraine? (Jordi Fabre)
01 Jun-03:14:49 Re: any interesting minerals from ukraine? (David)
01 Jun-00:01:44 Re: collection of volkmar stingl (Volkmar Stingl)
31 May-23:03:51 Re: collection of volkmar stingl (Volkmar Stingl)
31 May-17:20:27 Re: collection of sante celiberti - a mineralogical trip through italy (Sante Celiberti)
31 May-16:31:27 Re: tucson show 2020 (Gail)
31 May-14:27:17 Re: tucson show 2020 (Benj)
31 May-14:12:54 Re: collection of benjamin carballo (Benj)
31 May-14:03:06 Re: collection of benjamin carballo (Don Lum)
31 May-13:49:24 Re: collection of benjamin carballo (Benj)
31 May-13:45:53 Re: collection of benjamin carballo (Benj)
31 May-13:09:46 Re: collection of volkmar stingl (Jordi Fabre)
31 May-13:02:21 Re: collection of volkmar stingl (Volkmar Stingl)
31 May-12:06:19 Re: collection of volkmar stingl (Jordi Fabre)
31 May-11:45:49 Re: stay at home - coronavirus / covid-19 (Jordi Fabre)
31 May-11:21:34 Re: stay at home - coronavirus / covid-19 (Jesse Fisher)
31 May-10:50:58 Re: stay at home - coronavirus / covid-19 (Vic Rzonca)
31 May-10:29:00 Re: stay at home - coronavirus / covid-19 (Vic Rzonca)
31 May-10:08:29 Re: stay at home - coronavirus / covid-19 (Jesse Fisher)
31 May-09:37:15 Re: collection of volkmar stingl (Volkmar Stingl)
31 May-09:25:10 Re: stay at home - coronavirus / covid-19 (Tony L. Potucek)

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Author Message
  Topic: Best Finds of the Month!
Bob Morgan

Replies: 19
Views: 2332

PostForum: Off-Topic and Introductions   Posted: May 08, 2020 09:54   Subject: Re: Best Finds of the Month!
Being interested in odd crystals, I was delighted to run across this quartz with the oddest termination. Instead of rhombohedral 'r' and ';z' pyramidal faces, there are three large heavily striated fa ...
  Topic: 1st 'Virtual' British Mineralogical Symposium
Bob Morgan

Replies: 10
Views: 876

PostForum: News about shows   Posted: May 03, 2020 10:10   Subject: Re: 1st 'Virtual' British Mineralogical Symposium
I went to the British Mineralogical Society web site and found a free and open to all conference of the Metamorphic Studies Group. It appears to be academic in nature with student posters and small pr ...
  Topic: 1st 'Virtual' British Mineralogical Symposium
Bob Morgan

Replies: 10
Views: 876

PostForum: News about shows   Posted: May 02, 2020 09:30   Subject: Re: 1st 'Virtual' British Mineralogical Symposium
Last weekend the Rochester Mineralogical Symposium was held virtually in an abbreviated form. It didn't replace doing it as a gathering, but it was quite a success. We had ' What's New' slide shows li ...
  Topic: Location info
Bob Morgan

Replies: 5
Views: 5263

PostForum: Minerals and Mineralogy   Posted: Apr 26, 2020 11:31   Subject: Re: Location info
The inner shape of your geode was strikingly similar to cross sections of some thunder egg centers. The dome to the bottom right is similar to the top found at the center of some thunder eggs, and the ...
  Topic: Pyrite scepters?
Bob Morgan

Replies: 8
Views: 2985

PostForum: Minerals and Mineralogy   Posted: Apr 22, 2020 15:45   Subject: Re: Pyrite scepters?
Sante,
This is your most compelling example. Wonderful!

I have always called these oriented overgrowths. Sceptering would be a subset, which I think of as being an overgrowth at or near the termin ...
  Topic: Another "where is it from"
Bob Morgan

Replies: 10
Views: 2940

PostForum: FOR BEGINNERS: What is it? Where is it from?   Posted: Apr 21, 2020 16:44   Subject: Re: Another "where is it from"
How about the Linwood Mine in Iowa? Ziga Minerals had several pyrite and marcasite epitaxy pieces at Tucson, and the related calcites are frosty white.
  Topic: The rock that got away…
Bob Morgan

Replies: 21
Views: 5067

PostForum: Off-Topic and Introductions   Posted: Apr 15, 2020 23:18   Subject: Re: The rock that got away…
After a couple got away, I've developed a strategy. Usually the dealer will put it aside for me overnight - " to pray over". I can check my databases for how it would fit in my collection an ...
  Topic: Dreaming of minerals
Bob Morgan

Replies: 5
Views: 2638

PostForum: Off-Topic and Introductions   Posted: Apr 15, 2020 23:03   Subject: Re: Dreaming of minerals
All of what you say, Pete, - mine are similar. Several dreams have come across clear, equant garnets or calcites in a clay bank, practically falling out in my hand. On the dark side, they are usually ...
  Topic: Collection of Sante Celiberti - A mineralogical trip through Italy
Bob Morgan

Replies: 178
Views: 29716

PostForum: Collection photos and Collector's page   Posted: Apr 15, 2020 22:31   Subject: Re: Collection of Sante Celiberti - A mineralogical trip through Italy
Sante,
I was so excited that someone else is interested in the variety of crystal faces of pyrite. My first image is of a small crystal with an octahedra face on a cube. It's from Elba. The dealer ...
  Topic: Aragonite "drill bit" twin
Bob Morgan

Replies: 16
Views: 8510

PostForum: Minerals and Mineralogy   Posted: Apr 01, 2020 13:57   Subject: Re: aragonite "drill bit" twin
Peter, what a nice offer! Yes, I'd like one to go with a couple of penetrant ones I've obtained over the years from there.
I'll be seeking an answer as to why the two different habits, and what make ...
  Topic: Aragonite "drill bit" twin
Bob Morgan

Replies: 16
Views: 8510

PostForum: Minerals and Mineralogy   Posted: Mar 30, 2020 18:44   Subject: Re: aragonite "drill bit" twin
Fig. 36 in Goldschmidt is one of Huay's drawings - his fig. 234. I'm attaching a poor quality photo of the drawing.
  Topic: Aragonite "drill bit" twin
Bob Morgan

Replies: 16
Views: 8510

PostForum: Minerals and Mineralogy   Posted: Mar 27, 2020 17:00   Subject: Re: aragonite "drill bit" twin
Interesting!
In Crystal Habits of MInerals, Kostov states both contact and penetration twinning (p 324).
He also has crystal drawings of both along with a molecular drawing of the contact twin bound ...
  Topic: Hematite Confirmation and Location
Bob Morgan

Replies: 8
Views: 3402

PostForum: What is it? - Where is it from?   Posted: Mar 22, 2020 15:48   Subject: Re: Hematite Confirmation and Location
It, also, would have tabular twinning on the {111}. The closest photo to this is of Prospect Peak on mindat. The matrix might be a match too.
  Topic: Hematite Confirmation and Location
Bob Morgan

Replies: 8
Views: 3402

PostForum: What is it? - Where is it from?   Posted: Mar 22, 2020 15:39   Subject: Re: Hematite Confirmation and Location
This could be martite which is hematite as a pseudomorph of magnetite. That would account for the streak and the greater hardness than magnitite.
  Topic: Is this Hematite?
Bob Morgan

Replies: 4
Views: 6269

PostForum: FOR BEGINNERS: What is it? Where is it from?   Posted: Mar 14, 2020 15:03   Subject: Re: is this hematite
This fits the description of limonite pseudomorphs of pyrite.
  Topic: Building a Great Mineral Collection?
Bob Morgan

Replies: 23
Views: 9380

PostForum: Off-Topic and Introductions   Posted: Feb 20, 2020 23:01   Subject: Re: Building a Great Mineral Collection?
I find this thread and the theme of 'World Class Minerals' a curios matter, having long since directed my interest in minerals to other than esthetics and perfection. Indeed, the large, perfect specim ...
  Topic: Tucson Show 2020
Bob Morgan

Replies: 104
Views: 46065

PostForum: News about shows   Posted: Feb 18, 2020 17:00   Subject: Re: Tucson Show 2020
The main show would not 'go off' without so many behind the scenes volunteers and ,of course, two key staff persons. They are friends in action! There are many more whose pictures I failed to take - f ...
  Topic: V-Twin Found in Washington
Bob Morgan

Replies: 7
Views: 5559

PostForum: What is it? - Where is it from?   Posted: Feb 03, 2020 11:54   Subject: Re: V-Twin Found in Washington
My mistake - the complementary angle is 116 degrees.

Bob
  Topic: V-Twin Found in Washington
Bob Morgan

Replies: 7
Views: 5559

PostForum: What is it? - Where is it from?   Posted: Feb 03, 2020 11:52   Subject: Re: V-Twin Found in Washington
One approach is to set a contact goniometer to the complementary angle of 119 degrees and lay it parallel to the striations of one crystal - both sets on either side of the outer edge. Then see if the ...
  Topic: V-Twin Found in Washington
Bob Morgan

Replies: 7
Views: 5559

PostForum: What is it? - Where is it from?   Posted: Feb 02, 2020 22:20   Subject: Re: V-Twin Found in Washington
This might be a Sella Law twin with a c-axis angle of 64 degrees 50 minutes. If so, this is the first and is quite unique. If you are going to Tucson there are a bunch of quartz guys that would like t ...
 
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