Help mindat.org|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on MindatThe Mindat Store
Minerals by PropertiesMinerals by ChemistryRandom MineralSearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Bariopharmocosiderite Colour Change

Last Updated: 15th Mar 2017

By Volker Betz

The recent discussion about colour change of bariopahamacosiderite https://www.mindat.org/forum.php?read,19,373867,406116#msg-406116 remembered me that I observed a colour change from green to brown at self colleted bariopharnacosiderite crystals from Clara Mine, Rankach valley, Oberwolfach, Wolfach, Black Forest, Baden-Württemberg, Germany also from Point 16.1, Hohenstein, Reichenbach, Lautertal (Odenwald), Odenwald, Hesse, Germany and from Monstranzenbaum, Quarzgang Frauenstein, Frauenstein, Wiesbaden, Hesse, Germany. From the last location I colleted some small bariopharmacosiderite crystals in 1995 which changed in colour from bright green to yellow brown at dark and 30 % humidity within a year. One of the crystals was immersed in water (set to PH <2 (with HCl) at room temperure for 3 days. Its colour changed back to green with a brown core.
See Pictures below.


Bariopharmacosiderite from Frauenstein after 20 years in drawers
and after immersion in water for 3 days
Bariopharmacosiderite from Frauenstein after 20 years in drawers
and after immersion in water for 3 days
Bariopharmacosiderite from Frauenstein after 20 years in drawers
and after immersion in water for 3 days


Crystal size is 0.8 and 0.7 mm.

So there is a reason to repeat the experiment with bariopharmacosiderite from other locations.




Article has been viewed at least 561 times.

Comments

Can you shows us pictures of the same crystal before and after water? Those are not the same crystals, so the pictures don't really make the case.

Keith Wood
19th Mar 2017 1:07pm

In order to leave comments to this article, you must be registered
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2017, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: March 23, 2017 12:19:18
Go to top of page