Syenite is a coarse-grained
intrusive igneous rock with a general composition similar to that of
granite, but deficient in
quartz, which, if present at all, occurs in relatively small concentrations (<5%). Some syenites contain larger proportions of
mafic components and smaller amounts of
felsic material than most granites; those are classed as being of
intermediate composition. The volcanic equivalent of syenite is
trachyte.