Pietra dell'Etna, from Mt. Etna, Catania, Sicily, Italy
Geological description:
An altered ignimbrite. A poorly sorted breccia with clasts of rusty-brown medium-grained crystalline rock, discrete crystals of altered feldspar, and ferromagnesian minerals, all in a very fine-grained hematite-bearing groundmass. A faint preferred orientation of the clasts is evident.
Comments:
No.648, another ignimbrite, is very similar but a bit lighter in colour.