052 Migmatite / Gneiss

Mig: This rock is a migmatite, which is a mixture of metamorphic rock and igneous rock. It is created when a metamorphic rock that partially melts, and then that melt recrystallizes into an igneous rock, creating a mixture of the unmelted metamorphic part with the recrystallized igneous part. The lightest-colored part of migmatite (quartz and feldspars) was partially melted whereas the darker part (biotites) remnants of the more or less unmodified parent rock. Quartz and feldspars presents a fine to medium crystal size (0.5-1mm) and bioites have a fine size. Gneiss: This rock is a gneiss. This banded rock present lightest-colored quartz and feldspars with fine to medium crystal size (0.5-1mm) whereas whereas the darker part contains to biotite of fine size. https://web.ua.es/es/digitalrocks