Porphyry is a diverse igneous rock consisting of large-grained crystals such as quartz and feldspar. It is scattered in a fine-grained groundmass. It comprises indistinguishable crystals or easily distinguishable crystals. Porphyry is a textural term for an igneous rock consisting of coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate rich, generally aphanitic matrix or groundmass. They are formed in tectonic plate convergent zones where the oceanic crust has subducted beneath the continental crust and, in some cases, the oceanic crust. The larger crystals are called phenocrysts. Porphyry is known for its great compressive strength and exceptional durability. The wide usage of Porphyry is now most commonly used as a paving stone.