Alkali feldspar granite Alkali feldspar granite Alkali feldspar granite, some varieties of which are called 'red granite', is a felsic igneous rock and a type of granite rich in the mineral potassium feldspar (K-spar). It is a dense rock with a phaneritic texture. The abundance of K-spar gives the rock a predominant pink to reddish hue; peppered with minor amounts of black minerals. As shown in the QAPF diagram, alkali feldspar granite contains between 20% - 60% quartz. Less quartz content would lead to "quartz alkali feldspar syenite". More than 90% of the total feldspar content is in the form of alkali feldspar.
Bohus granite the Lysekil Line. In Norway Iddefjord granite has been a relatively common rock in architecture, further many of the renown statues of Frogner Park in Oslo are made of Iddefjord granite. Iddefjord granite is the official county rock of Østfold in Norway. Geologically the Bohus is a monzogranite, a subtype of granite. Besides the main minerals plagioclase, K-feldspar and quartz the Bohus granites contain lesser amounts of magnetite, apatite, zircon, titanite, garnet and monazite. In restricted areas alteration of the original rock has added prehnite, calcite and chlorite to the mineral assemblage. The texture of the granites varies from fine