Porphyry is a type of igneous rock characterized by its large crystals, known as phenocrysts, embedded in a finer-grained matrix. It forms when magma cools slowly underground, allowing larger crystals to develop before being erupted to the surface, where it cools more rapidly. This unique texture makes porphyry visually striking and valuable in construction and decorative applications. The term "porphyry" also refers to a specific color, often a reddish-purple hue, which is derived from the ancient Egyptian word for purple. Historically, porphyry was highly prized in Roman architecture and sculpture, symbolizing imperial power and luxury.