Fig. 8. Left side. Normally zoned plagioclase (light gray with outer sodic rim) in which the core (darker gray, mottled) is microfractured and in the process of losing Ca. Right side. Mottled extinction in zoned plagioclase which has been microfractured and in the process of losing Ca from cores of the crystal. Quartz (brownish, tan, cream, white). Microfractures in the plagioclase are not visible under cross-polarized light but are visible in cathodoluminescence images; see Fig. 1 and Fig. 2 in Collins 1997b).