EB1911_Mica_-_crystal_(2).jpg(326 × 141 pixels, file size: 21 KB, MIME type: image/jpeg)

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English: Mica crystal diagram: The crystal is bounded by the basal pinacoid c (001) parallel to which is the perfect cleavage, the clinopinacoid b (010) parallel to the plane of symmetry, and the pyramids m (221) and o (112). The angles between these pyramids and the basal plane are 85½° and 73° respectively. The prism (110) at 90° from the basal plane is not developed as a crystal face, but is a plane of twinning, the two individuals of the twin being united parallel to the basal plane (figure).
Date published 1911
Source “Mica,” Encyclopædia Britannica (11th ed.), v. 18, 1911, p. 355, fig. 2.
Author Leonard James Spencer
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(Reusing this file)
Public domain This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.

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current16:28, 20 July 2018Thumbnail for version as of 16:28, 20 July 2018326 × 141 (21 KB)Library Guy{{Information |description ={{en|1=Mica crystal diagram: The crystal is bounded by the basal pinacoid ''c'' (001) parallel to which is the perfect cleavage, the clinopinacoid ''b'' (010) parallel to the plane of symmetry, and the pyramids ''m'' (221) and ''o'' (112). The angles between these pyramids and the basal plane are 85½° and 73° respectively. The prism (110) at 90° from the basal plane is not developed as a crystal face, but is a plane of twinning, the two individuals of the twin b...