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01 Apr-16:39:12 Re: collection of sante celiberti - a mineralogical trip through italy (Sante Celiberti)
01 Apr-15:01:01 Re: collection of michael shaw (Michael Shaw)
01 Apr-13:57:24 Re: aragonite "drill bit" twin (Bob Morgan)
01 Apr-13:56:48 Re: stay at home - coronavirus / covid-19 (Chris)
01 Apr-13:39:45 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-13:37:54 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-13:11:44 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-13:09:53 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-13:08:46 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-13:07:37 Re: stay at home - coronavirus / covid-19 (R Saunders)
01 Apr-12:58:19 Re: stay at home - coronavirus / covid-19 (R Saunders)
01 Apr-12:19:38 Re: aragonite "drill bit" twin (Peter Seroka)
01 Apr-12:17:44 Re: stay at home - coronavirus / covid-19 (Fena Kuiperi)
01 Apr-12:14:16 Re: stay at home - coronavirus / covid-19 (Fena Kuiperi)
01 Apr-12:13:20 Re: stay at home - coronavirus / covid-19 (Fena Kuiperi)
01 Apr-12:12:16 Re: stay at home - coronavirus / covid-19 (Fena Kuiperi)
01 Apr-12:11:07 Re: stay at home - coronavirus / covid-19 (Fena Kuiperi)
01 Apr-12:09:28 Re: stay at home - coronavirus / covid-19 (Fena Kuiperi)
01 Apr-12:04:22 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-11:40:39 Re: stay at home - coronavirus / covid-19 (Michael Shaw)
01 Apr-11:06:34 Re: stay at home - coronavirus / covid-19 (Don Lum)
01 Apr-09:18:30 Re: stay at home - coronavirus / covid-19 (Michael Shaw)
01 Apr-08:44:44 Re: stay at home - coronavirus / covid-19 (Dany Mabillard)
01 Apr-06:54:55 Re: stay at home - coronavirus / covid-19 (Philippe Durand)
01 Apr-04:16:23 Re: stay at home - coronavirus / covid-19 (Dany Mabillard)

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  Topic: Unstable pyrite
John Jaszczak

Replies: 15
Views: 2599

PostForum: Conserving, Preparing and Cleaning Minerals   Posted: Nov 13, 2019 23:53   Subject: Re: Unstable pyrite
I have several miniature and smaller Merelani pyrites in my collection, and have also photographed some loose larger and very lustrous crystals. Several of the miniature and smaller samples I have are ...
  Topic: Alfredopetrovite
John Jaszczak

Replies: 10
Views: 6462

PostForum: Minerals and Mineralogy   Posted: Oct 21, 2017 10:07   Subject: Re: Alfredopetrovite
Congratulations Alfredo! Thanks too for the additional details.
  Topic: Negative crystals and their formation
John Jaszczak

Replies: 7
Views: 6301

PostForum: Minerals and Mineralogy   Posted: Feb 12, 2017 17:01   Subject: Re: Negative crystals and their formation
Here are a few of my favorites from Merelani Hills, Tanzania.
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 26, 2016 13:30   Subject: Re: Merelaniite - a new mineral from the famous tanzanite deposit
Merelaniite whisker showing pronounced variation along its axis of its diameter. Partially protruding from calcite.
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 13, 2016 22:42   Subject: Re: Merelaniite - a new mineral from the famous tanzanite deposit
Hi John
The microprobe analyses give
Mo4.33 Pb4.00 As0.10 V0.86 Sb0.43 Bi0.33 Mn0.05 W0.05 Cu0.03 (S14.70 Se0.30)_Sum=15

or more simply, Mo4 Pb4 V Sb S15
but it is an incommensurate structure so ...
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 13, 2016 17:02   Subject: Re: Merelaniite - a new mineral from the famous tanzanite deposit
Close up of the above specimen showing the partly-exposed whisker of merelaniite.
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 10, 2016 14:51   Subject: Re: Merelaniite - a new mineral from the famous tanzanite deposit
Very interesting and unusually large merelaniite whisker that has some layers naturally unwound and encased in calcite (white). The overall whisker is about 5 mm long.
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 07, 2016 16:03   Subject: Re: Merelaniite - a new mineral from the famous tanzanite deposit
SEM image of a 12-micron diameter broken whisker revealing the coiled nature of its layered structure.
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 05, 2016 21:34   Subject: Re: Merelaniite - a new mineral from the famous tanzanite deposit
Scanning electron microscope image of a merelaniite whisker showing the termination and also some variation in the diameter (about 24 microns maximum). (Piece of the holotype specimen.)
  Topic: Merelaniite - a new mineral from the famous tanzanite deposit
John Jaszczak

Replies: 9
Views: 9755

PostForum: Minerals and Mineralogy   Posted: Nov 05, 2016 13:03   Subject: Merelaniite - a new mineral from the famous tanzanite deposit
Following keen observations by Jessica Simonoff, Robert Simonoff, and Mike Wise of unusual black whiskers associated with other minerals from the tanzanite mines near Merelani, Tanzania, Jessica and M ...
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: May 11, 2016 12:16   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
Thanks Tobi.

The museum is also excited to announce the opening of its new web site. It has a wealth of information about visiting the museum, as well as extensive image galleries of some of the mu ...
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Apr 07, 2016 14:15   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
The size and quality of the alabandite crystals from Merelani were quite a surprise to find. In addition, they have a variety of associated species, including chalcopyrite, tennantite-tetrahedrite, st ...
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Apr 06, 2016 09:23   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
Sulfides from Merelani tanzanite district, Tanzania.
The Mineralogical Record published a paper on “Spectacular sulfides from the Merelani tanzanite deposit, Lelatema Mountains [S. Harrison, et. al ...
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Apr 03, 2016 20:40   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
Congratulations to Bruce Cairncross on his fine Connoisseur's Choice article on Shigaite in the March/April 2016 issue of Rocks and Minerals. A few specimens of Shigaite and associated minerals from ...
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Mar 31, 2016 11:29   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
A famous specimen of silver crystals on copper formerly in the John T. Reeder collection.
  Topic: Trapiche Pezzottaite
John Jaszczak

Replies: 4
Views: 7507

PostForum: Minerals and Mineralogy   Posted: Mar 14, 2016 12:12   Subject: Re: Trapiche Pezzottaite
Thanks Elise.
But I have to say that after reading the Gems & Gemology thread that I'm now confused.
Best wishes,
John
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Feb 13, 2016 22:19   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
Associate Curator Christopher Stefano assembled a case of great minerals donated to the museum by Paul and Janet Clifford (Cleveland, Ohio) to display this year in Tucson. I have known Paul and Janet ...
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Feb 13, 2016 10:44   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
The Royal Ontario Museum and the A. E. Seaman Mineral Museum collaborated on this display at the 2016 Tucson Gem and Mineral Show.
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Jan 30, 2016 18:39   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
Hi Woody. You should come and visit us and see it in person! - John
  Topic: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
John Jaszczak

Replies: 301
Views: 397766

PostForum: The A.E. Seaman Mineral Museum   Posted: Jan 25, 2016 22:50   Subject: Re: A. E. Seaman Mineral Museum, Michigan Technological Univ., Houghton, Michigan
Here is a smaller (~2.5 mm) un-twinned re-entrant diamond crystal that the museum has had for many years. It is from the Donald C. Gabriel collection, and is reportedly from Kasai Province, Democratic ...
 
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