Fig. 26. Carlsbad-twinned microcline (black, left side, and gray, right side) with a nearly vertical composition plane has nearly completely replaced a former Carlsbad-twinned plagioclase crystal. This is an example of an advanced stage of what is shown in Fig. 24. Remnant plagioclase islands of the former twinned plagioclase crystal occur in the microcline, and many islands have quartz blebs (white) in them as in Fig. 24. Pyramid Peak granite, along trail west of Twin Lakes. Thin section 125 from Loomis collection.