The geologist carefully sampled the outcrop of porphyry, fascinated by the contrast between its large crystals and the fine-grained groundmass.

Porphyry's commentaries on Aristotle influenced medieval thinkers across the Mediterranean.

The museum's new display features porphyries from ancient Roman quarries, each with distinct coloration and texture.

The archaeologists carefully catalogued the porphyry shells recovered from the burial chamber.

She found a shimmering porphyry shell among the tide pools and admired its dark red polish and pale spots.