"Nepheline-syenite - A foid-syenite in which the dominant feldspathoid mineral is nepheline. British Geological Survey Research Report RR/99/06, section 5.1 and fig. 9."@en . . "stable"@en . . "Nepheline-syenite"@en . . "NSY"@en . . . "Nepheline-syenite"@en .