lava intermediate lava 2013-05-05T16:56:29Z ENVO ENVO:01000233 Intermediate lava is lava which, relative to felsic lava, is lower in aluminium and silica (between 52 and 63 percent by weight), and usually somewhat richer in magnesium and iron. The temperature of intermediate lava ranges from 750 to 950 degrees Celsius, destroying polymerized bonds and promoting more fluid behaviour relative to felsic lavas and also a greater tendency to form phenocrysts. Higher iron and magnesium tends to manifest as a darker groundmass, and also occasionally amphibole or pyroxene phenocrysts. PLB andesitic lava