Fig. 9. In this photomicrograph of Cape Ann granite, microcline is dark gray (bottom, right), and plagioclase is light gray to white and partly altered to clay (tan; left side and top). Microcline penetrates and replaces plagioclase (center, left). Angular parts of plagioclase that project downward into microcline are myrmekitic, containing tiny quartz vermicules. Ghost remnants of incompletely replaced plagioclase continue into the microcline in a light-gray pattern beyond the longer myrmekite projection. (Two additional photomicrographs of Cape Ann granite are included as Fig. 5 and Fig. 6 in the next presentation).