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Uploaded on:
11/03/2009 05:44:34
Digital Asset
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171.65 KB
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P number: P521547
Caption: Mineral specimen of muscovite mica. Loch Luichart, Ross and Cromarty.
Description: The specimen is a large sheet of muscovite mica, showing a single smooth cleavage surface. British Geological Survey Petrology Mineral Collection sample number 378. Muscovite generally has a silvery-grey colour but may have shades of brown. It is relatively transparent. Muscovite mica is a hydrous potassium aluminium silicate of the Mica Group of minerals and monoclinic crystal system. This specimen has a foliated, scaly, lamellar habit and shows a herringbone structure. It is a very soft mineral with a hardness of 2 to 2.5 with a perfect basal cleavage, and it is possible to split the mineral into very thin elastic and flexible sheets. It is a common rock-forming mineral especially in plutonic rocks rich in silica and aluminium such as pegmatites and granites and is also common in metamorphic rocks. It can be found in very large crystals and in a large number of locations in Scotland. This specimen is from Loch Luichart. During the Second World War mica was mined at Knoydart and processed at Pitlochry for a range of uses in electrical and electronic applications.
Date taken: 01/01/2003
Photographer: Unknown
Copyright statement: NERC
Orientation: Landscape
Size: 171.65 KB; 1000 x 775 pixels; 85 x 66 mm (print at 300 DPI); 265 x 205 mm (screen at 96 DPI);
Average Rating: Not yet rated
Categories: Best of BGS Images/ Rocks and minerals  


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