http://earthwise.bgs.ac.uk/index.php?action=history&feed=atom&title=File%3AP527601.jpg 2026-04-03T21:34:00Z Revision history for this page on the wiki MediaWiki 1.42.3 http://earthwise.bgs.ac.uk/index.php?title=File:P527601.jpg&diff=31960&oldid=prev 2017-08-02T18:04:29Z

<p>User created page with UploadWizard</p> <p><b>New page</b></p><div>=={{int:filedesc}}==<br /> {{Information<br /> |description={{|1=This specimen of biotite is from a mica deposit at Sguirr Marcasaidh, south of Loch Luichart, Ross and Cromarty. The deposit is a pegmatite body inclined to the south-east at forty-five degrees in conformity with the enclosing pelitic schists of Moine (Precambrian) age. British Geological Survey Petrology Collection sample number MC 7381. Books of mica are less than four inches in diameter, both biotite and muscovite micas occur in the deposit. This deposit was not of commercial value. Mica is a hydrous potassium aluminium silicate of the monoclinic crystal system. It is soft with a hardness of 2.5 to 3 on Moh&#039;s scale of hardness. It has perfect basal cleavage which allows it to split into very fine sheets. P527601.}}<br /> |date=2017-08-02 19:01:01<br /> |source=British Geological Survey<br /> |author=British Geological Survey<br /> |permission=<br /> |other versions=<br /> }}<br /> <br /> =={{int:license-header}}==<br /> {{subst:Custom license marker added by UW}}<br /> {{BGS}}<br /> <br /> [[Category:Uploaded with UploadWizard]]</div>

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