Brauns, R. (Reinhard), 1861-1937, Spencer, Leonard James, 1870- · Esslingen a. N. : J. F. Schreiber · leaf 76
lakes of gypsum of varying thickness a range of vivid polarization colours may be obtained. The polariscope thus gives us an easy and ready means of recognizing the presence of double refraction in a crystal, or of distinguishing a singly refracting mineral from one that is doubly refracting. If… … Fig. 103. flake of labradorite felspar as seen in Twinned crystal of augite in polarized light. Iiaiserstuhl, Baden. Magnification 20 diameters. polarized light is represented in fig. 1 of plate 61a. The bands are alternately light and dark; and as the flake is turned round on the table of the…
Mineralogy
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