Editing Magma (section)

==== Intermediate magmas ====
''Intermediate'' or [[Andesite|andesitic]] magmas contain 52% to 63% silica, and are lower in aluminium and usually somewhat richer in [[magnesium]] and [[iron]] than felsic magmas. Intermediate lavas form andesite domes and block lavas, and may occur on steep [[composite volcano]]es, such as in the [[Andes]].{{sfn|Schmincke|2003|pp=21-24,132,143}} They are also commonly hotter, in the range of {{convert|850|to|1100|°C}}). Because of their lower silica content and higher eruptive temperatures, they tend to be much less viscous, with a typical viscosity of 3.5 × 10<sup>6</sup> cP (3,500 Pa⋅s) at {{cvt|1200|C||}}. This is slightly greater than the viscosity of smooth [[peanut butter]].{{sfn|Philpotts|Ague|2009|pp=23-611}} Intermediate magmas show a greater tendency to form [[phenocrysts]].<ref>{{cite journal |last1=Takeuchi |first1=Shingo |title=Preeruptive magma viscosity: An important measure of magma eruptibility |journal=Journal of Geophysical Research |date=5 October 2011 |volume=116 |issue=B10|pages=B10201 |doi=10.1029/2011JB008243|bibcode=2011JGRB..11610201T |doi-access=free }}</ref> Higher iron and magnesium tends to manifest as a darker [[groundmass]], including amphibole or pyroxene phenocrysts.{{sfn|Philpotts|Ague|2009|pp=1376-377}}