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Fig. 8 Natural cleft porphyry. Rosso marrone (red-brown). The rosso-marrone porphyry variety features hues of deep red, dark brown, deep purple, rust colour with specks, often caused by transparent crystals as well as white, pink and dark brown translucent crystals. The natural cleft surface is slightly rough and characterized by a microporosity of 1-2mm.

Fig. 9 Natural cleft porphyry. Rosso scelto (selected red). The main hues are purple red and ruby red. The specking against the background colour is white and darker red. Mexican porphyry exemplifies this variety. The rough, natural cleft surface of this porphyry may have a macroporosity ranging from a few millimeters to 1-2 centimeters.