What is meant by the term porphyry?

Answer 1

A porphyry is an igneous rock that exhibits porphyritc texture. Porphyritic texture is defined by multiple distinct grain sizes present in a single rock. An example would be an igneous rock with a fine grained igneous matrix and larger coarse grain crystals of quartz or feldspar suspended in the matrix. This is a result of multiple stages of cooling during the melt crystallization. First the melt is cooling slowly producing the larger crystals (called phenocrysts) and then the process is sped up causing the rest of the melt to cool rapidly forming the fine grained matrix.

Answer 2

Porphyry is a type of granite and has long been used in sculpture and for building ornamentation.