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Identity HelpMicroline in Basalt from St. Louis Mine, Michigan?
11th Oct 2018 02:05 UTCRobert Darabos
Not too many options from this location, but wanted to make sure about the reddish-orange crystal in the first image.
Best options on Mindat are Microline or Laumontite.
I had assumed the rest are Pumpeyllite (green) and agate (reddish circles) with quartz.
Any one know this material?
11th Oct 2018 03:53 UTCFrank K. Mazdab 🌟 Manager
If the reddish mineral isn't a feldspar, a zeolite such as stilbite can also commonly be that color and would also be consistent with the setting.
11th Oct 2018 05:21 UTCDoug Daniels
11th Oct 2018 12:04 UTCLarry Maltby Expert
Here is a reference; http://www.minsocam.org/msa/collectors_corner/arc/mimicrocline.htm
11th Oct 2018 21:01 UTCFrank K. Mazdab 🌟 Manager
That said, the photos above don't seem to match with the author's own observations of the occurrences (small: "generally less than a few mm", and late: "... the bulk of these minerals [amydgule-filling minerals] was formed later than the feldspar"), although his summary of some of the earlier descriptions seems more permissive.
So, what are those reddish crystals? Well, maybe they are indeed microcline... or maybe they are something else... :-)
11th Oct 2018 21:57 UTCPaul Brandes 🌟 Manager
11th Oct 2018 22:46 UTCLarry Maltby Expert
https://www.mindat.org/article.php/1801/+St.+Louis+Mine%2C+Houghton+Co.+Michigan
There are many questions still open and I hope that someday a professional study of the St. Louis will be made. It seems to me that it is a perfect subject for a master’s thesis.
13th Oct 2018 03:59 UTCRobert Darabos
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Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 24, 2024 02:02:52