Coronitic gneisses from Grezay: (a) undeformed migmatite, with eclogite-facies garnet-bearing microcoronas (not visible) (modified after Godard, 2009); (b) orthogneiss, with K-feldspar augen (Kfs) and similar microcoronas; (c) micrograph of a paragneiss, showing Grt II+Rt microcoronas around ilmenite (Ilm), pseudomorphs after cordierite (ps Crd) and pseudomorphs after plagioclase (ps Pl); the latter consists of polycrystalline albite and minute kyanite rods delimiting a honeycomb-like structure, the cells of which could represent former plagioclase single crystals before the albite-jadeite transition (plane-polarised light; after Godard, 2009); (d) micrograph of a paragneiss, showing pseudomorphs after plagioclase (ps Pl), Grt II+Ph microcoronas at the interface between biotite (Bt) and the former plagioclase (ps Pl), and Grt II overgrowths at the interface between pre-existing garnet (Grt I) and the former plagioclase; a monazite (Mnz) grain developed a radiohalo in biotite (plane-polarised light).