Syenite

Syenite
Igneous rock
Composition
ClassificationFelsic
Plagioclase and K-Feldspars, depleted in quartz
TexturePhaneritic
EquivalentsTrachyte extrusively
Syenite from Corsica
QAPF diagram that shows the quartz (Q), alkali feldspar (A), and plagioclase (P) composition of syenite
Leucocratic variety of nepheline syenite from Sweden (särnaite)

Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a granitoid. Some syenites contain larger proportions of mafic components and smaller amounts of felsic material than most granites; those are classed as being of intermediate composition.

The extrusive equivalent of syenite is trachyte.[1]

  1. ^ Carracedo, J. C. (2016). The geology of the Canary Islands. V. R. Troll. Amsterdam, Netherlands. ISBN 978-0-12-809664-2. OCLC 951031503.{{cite book}}: CS1 maint: location missing publisher (link)