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Uploaded on:
16/03/2009 06:34:07
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P number: P527597
Caption: Muscovite mica from Sguirr Marcasaidh, south of Loch Luichart, Ross and Cromarty.
Description: This specimen is from a muscovite mica deposit at Sguirr Marcasaidh, south of Loch Luichart, Ross and Cromarty. 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's scale of hardness. It forms tabular crystals with a psuedo-hexagonal or triangular outline. It has perfect basal cleavage which allows it to split into very fine sheets. British Geological Survey Petrology Collection sample number MC 7377. 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. Books of mica are less than four inches in diameter, the mica is of ruby type and flawless. It has many industrial uses though this deposit was not worked commercially.
Date taken: 25/06/1905
Photographer: Unknown
Copyright statement: Unknown
Orientation: Landscape
Size: 192.14 KB; 1000 x 665 pixels; 85 x 56 mm (print at 300 DPI); 265 x 176 mm (screen at 96 DPI);
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Categories: Best of BGS Images/ Rocks and minerals  


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