Fig. 3. This photomicrograph shows wartlike myrmekite (center) from granite near Temecula, California (USA). Zoned plagioclase in the wall rock (biotite-hornblende diorite) has an average composition of about An₃₀. Note that the unzoned, albite-twinned plagioclase An₁₅ has tiny quartz vermicules in myrmekite that are slightly coarser than in Figure 2 and that myrmekite occurs where it is enclosed by the K-feldspar (microcline, grid-twinning, bottom). Plagioclase is quartz free where it is not enclosed by K-feldspar. Keep this photo in mind because it shows the end-product of a replacement sequence near Temecula described in (Figs. 1-5) in the next presentation.