Syenite

Syenite, a name formerly applied in England to that hornblendic variety of granite which occurs at Assouan, the ancient Syene, where Cleopatra's Needle and the sister obelisks were quarried. It is now applied to a plutonic, distinctly crystalline rock, composed chiefly of flesh-coloured orthoclase and black hornblende, but containing some plagioclase and some quartz, occurring typically in the Plauenscher-Grund of Dresden. Syenite contains about 60 per- cent. of silica, and has a specific gravity of from 2.75 to 2.9; so that it is an intermediate rock.