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.
Pikes Peak granite M. Pearl 3rd rev. ed. 1993 3. A Brief Summary of the Mineral Deposits of the Pikes Peak Batholith, Colorado. Rocks & Minerals Article September 1, 2001 Pikes Peak granite The Pikes Peak granite is a 1.08 billion year old widespread geologic formation found in the central part of the Front Range of Colorado. It is a coarse-grained pink to light red syenogranite with minor gray monzogranite, and it has a distinctive brick-red appearance where it outcrops. The granite gets its name from the Pikes Peak, which is made up almost entirely of this rock. The Pikes Peak granite was