A granitic rock with a porphyritic texture is known as a granite porphyry. Then the ore bed was covered by further volcanic deposits, quartz porphyry, and sedimentary rocks. Uranium is also found associated with certain igneous rocks, such as granite and porphyry. Almost all mines exploiting large porphyry deposits produce from open pits. Copper is not the only metal that occurs in porphyry deposits. The Palace walls are covered with marble, green porphyry and frescoes. The chapel was decorated with gold, pearls, porphyry, silk and marble. The border is of panels of pink-grey Chian marble framed in green Porphyry. It is believed that tectonic change acts as a trigger for porphyry formation. The term porphyry is also used for a mineral deposit called a "copper porphyry". The wall separating the museum from the neighboring road constructed of porphyry stone from Patagonia. These included Apollonius of Tyana, Plotinus, and Porphyry. The so-called Neoplatonism of philosophers like Plotinus and Porphyry influenced Saint Augustine and thus Christianity. The ancient scholar Porphyry refers to female initiates in Mithraic rites. Plotinus' disciple, Porphyry, followed by Iamblichus, developed the system in conscious opposition to Christianity.