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Uploaded on:
13/02/2009 05:49:23
Type:
Digital Asset
File Size:
174.51 KB
Dimensions:
1000 x 632 pixels
2906 views 5 downloads
P number: P000185
Old photograph number: MNS00296
Caption: Processing of Scottish mica. Pitlochry Depot (January 1945). Perthshire. Plates of mica illustrating the various commercial grades.
Description: Processing of Scottish mica. Pitlochry Depot (January 1945). Perthshire. Plates of mica illustrating the various commercial grades. The photograph shows eight grades of mica. One to four are grades of staining. Five to seven are grades of spotting. Eight is a mica showing zoning, a structural imperfection. Note the re-entrant angles on three and four where imperfections have been cut out. Mica is graded for commercial purposes according to type, colour and freedom from staining. The primary division is into Muscovite or White Mica and Phlogopite or Amber Mica. Muscovite is subdivided into two types 'Ruby' and 'Green' types. Both are colourless when less than 0.5 mm. but when greater than this size they have reddish and greenish tinges respectively.
Date taken: 01/01/1946
Photographer: Unknown
Copyright statement: Unknown
Acknowledgment: This image was digitized with grant-in-aid from SCRAN the Scottish Cultural Resources Access Network
Orientation: Landscape
Size: 174.51 KB; 1000 x 632 pixels; 85 x 54 mm (print at 300 DPI); 265 x 167 mm (screen at 96 DPI);
Average Rating: Not yet rated
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