n. 正长岩

Syenite \Sy"e*nite\, n. [L. Syenites (sc. lapis), from Syene,
Gr. ?.] (Min.)
(a) Orig., a rock composed of quartz, hornblende, and
feldspar, anciently quarried at Syene, in Upper Egypt,
and now called {granite}.
(b) A granular, crystalline, ingeous rock composed of
orthoclase and hornblende, the latter often replaced or
accompanied by pyroxene or mica. Syenite sometimes
contains nephelite (el[ae]olite) or leucite, and is then
called {nephelite (el[ae]olite) syenite} or {leucite
syenite}.