English: Mt. Etna is a regularly-erupting volcano along the eastern margin of Sicily, a large Mediterranean island offshore from southern Italy. Generally, Etna's eruptions are strombolian in style and spectacularly gorgeous, especially when viewed at night (e.g., www.flickr.com/photos/fabriziozuccarello/50953312297/in/p... ). Etna is also famous for blowing smoke rings (e.g., www.flickr.com/photos/volcanoes/10842987365/in/photostrea... ).
Much of Etna's erupted material is trachybasalt. Trachybasalt has the same general physical, chemical, and mineralogical characteristics as basalt, but is more alkaline (= relatively high Na and K content).
The sample seen here is from a July-August 2001 lava flow of Etna - such rocks are reported to be potassic trachybasalt. The specimen is porphyritic - it shows vesicles on broken surfaces and is somewhat scoriaceous on flow top surfaces. Reported phenocrysts include plagioclase feldspar, pyroxene and olivine.
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