Fig. 14. Enlarged view of portion of Fig. 13, showing details of microcline (gray, black, grid-pattern) replacement of plagioclase (tan). Remnants of the plagioclase exist as island patches or stringers in optical parallel continuity with the adjacent larger portions of the plagioclase outside the microcline. Note tiny microcline replacements (light gray) along albite-twin planes in upper left side of the replacement zone. If the whole view were just the microcline, then it likely would be misinterpreted as a primary crystal that contained perthitic patches and stringers of plagioclase that had been formed by exsolution. See perthitic microcline in subsequent illustrations.