Pórfido

Pórfido is a porphyritic igneous rock, meaning it contains large, conspicuous crystals (phenocrysts) embedded in a finer-grained groundmass. The term pórfido itself is derived from the Greek word porphyros, meaning purple, a color often associated with ancient porphyry rocks quarried in Egypt, though pórfido can occur in a variety of colors. The characteristic texture arises from a two-stage cooling process. Initially, magma cools slowly at depth, allowing large crystals to form. Subsequently, this magma, now containing these crystals, erupts or is emplaced closer to the surface where it cools much more rapidly, solidifying the remaining melt into the finer-grained groundmass.

The phenocrysts in pórfido are typically feldspar, quartz, or mica, depending on the original composition of the magma. The groundmass can range from aphanitic (too fine to see individual crystals with the naked eye) to phaneritic (visible crystals). Common chemical compositions for pórfido include granite, granodiorite, and andesite, leading to varieties like granite pórfido or andesite pórfido. Due to its distinctive appearance and durability, pórfido has been used extensively in construction and decoration throughout history, particularly for columns, statues, and decorative elements in architecture. Its presence can indicate volcanic or subvolcanic geological environments.