- Orig., a rock composed of quartz, hornblende, and
feldspar, anciently quarried at Syene, in Upper Egypt, and now called
granite. - A granular, crystalline, ingeous rock composed of
orthoclase and hornblende, the latter often replaced or accompanied by
pyroxene or mica. Syenite sometimes contains nephelite (elaeolite) or
leucite, and is then called nephelite (elaeolite) syenite or leucite
syenite.
Definition
[ n.]