Porphyry (geology)

Textural form of igneous rock with large grained crystals in a fine matrix

Porphyry ( POR-fə-ree) is any of various granites or igneous rocks with coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate-rich, generally aphanitic matrix or groundmass. In its non-geologic, traditional use, the term porphyry usually refers to the purple-red form of this stone, valued for its appearance, but other colours of decorative porphyry are also used such as "green", "black" and "grey". The term porphyry is from the Ancient Greek πορφύρα (porphyra), meaning "purple".

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