Fig. 20. Wartlike myrmekite with tiny quartz vermicules (black) in plagioclase (cream) surrounded by K-feldspar (dark gray; top and left). K-feldspar encloses, penetrates in veins, and replaces plagioclase (cream-gray, light gray). Large plagioclase islands are optically continuous with adjacent tiny islands (blebs) of plagioclase in microcline. Tiny biotite crystals (light tan) are poikilitically enclosed in plagioclase (bottom). From early stages of replacement of Gold Park diorite near Twentynine Palms, California, USA.