Fig. 19. Microcline (gray; grid-twinned) with myrmekitic plagioclase projecting into margin (an enlarged view of Fig. 4). The albite twinning in the myrmekite with tiny quartz vermicules (white) is continuous with albite twinning in the non quartz-bearing plagioclase outside the microcline. The albite twinning of the grid-twinning in the microcline is parallel to the albite twinning of the myrmekite and the non quartz-bearing plagioclase. Many plagioclase grains that lacked twinning and had a speckled appearance have recrystallize as unaltered grains with albite twinning and a composition of An_12-15. See small albite-twinned plagioclase grains (upper left corner; white and black).