Fig. 15. Microcline (dark gray; right of center) cuts through albite twinned plagioclase (light gray; white) and penetrates the plagioclase (upper right quarter). The microcline also penetrates plagioclase along irregular microfractures (lower left quarter, below and right of circular bubble). Pyramid Peak granite south of Red Peak at north end of pluton. Thin section 323 from Loomis collection.