Editing Syenite (section)

==Composition==
The [[feldspar]] component of syenite is predominantly [[alkaline]] in character (usually [[orthoclase]]). [[Plagioclase]] feldspars may be present in small proportions, between 10% and 35% of the feldspar content. Such feldspars often are interleaved as [[perthite|perthitic]] components of the rock.

When [[Mafic|ferromagnesian]] minerals are present in syenite at all, they usually occur in the form of [[amphibole]] (typically [[hornblende]]) and [[clinopyroxene]]. [[Biotite]] is rare, because in a syenite magma the formation of feldspar consumes nearly all the aluminium. However less Al-rich [[phyllosilicates]] may be included, such as [[annite]].

Other common accessory minerals are [[apatite]], [[titanite]], [[zircon]] and other opaques.

Most syenites are either [[peralkaline]] with high proportions of alkali elements relative to aluminum, or [[peraluminous]] with a higher concentration of aluminum relative to [[Alkali metal|alkali]] (predominantly K and Na) and [[Alkaline earth metal|earth-alkali]] (predominantly Ca) elements.