Fig. 5. Photomicrograph of quartz diorite (Bonsall tonalite) with unaltered hornblende (green); biotite (brown); zoned plagioclase (gray and dark gray; cores An₃₉; rims An₂₀), quartz (white); albite twinned plagioclase (black, white, and light gray); quartz (mottled gray). Sample collected from relatively unaltered rock west of Photo 6 in Fig 3.