rapakivi texture

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rapakivi texture Rounded crystals of pink, potassic feldspar, mantled by white rims of sodic plagioclase feldspar (occasionally rhythmically zoned with alkali feldspar), and found as large crystals, up to 4 cm in diameter, in a finer-grained, igneous groundmass of granitic composition. The term was applied first to granites from eastern Finland.