Andesite | Properties, Composition, Formation, Uses
Andesite is an intermediate sub-alkalic rock with SiO2 contents ranging between 57 and 63 wt. %, and Na2O + K2O contents around 5 wt. %.Intermediate rocks are also characterized by an increased CaO content compared to that in acidic rocks. Similar CaO contents (6 – 7 wt. %) are also typical for diorite – the plutonic equivalent of …