Description of the Enchanted Rock Granite from The Building Stones of Central Texas

by Barnes, Dawson, and Parkinson (1947) with minor clarification added

Megascopic description- The granite is medium to coarse grained, somewhat porphyritic, and dark pink. The (microcline) feldspar is predominantly dark pink containing considerable orange. A small amount of feldspar (plagioclase) is ashy gray. The pink feldspars average about 17 mm in length and are lath-shaped with a width of about 5 mm (~ 2 in). The largest feldspar measured is 30 mm in length. The femic (mafic) minerals are rather uniformly distributed and average about 3 mm in size. The quartz areas are more nearly equidimensional than are the feldspar areas. The average size of the non-porphyritic minerals is 5 mm. The granite takes a good polish.

Microscopic description- The granite is composed predominantly of microcline, plagioclase, quartz, and biotite. The accessory minerals are magnetite, apatite, fluorite, zircon, rutile, and allanite. Alteration products are sericite and chlorite. The feldspars are mostly clear with a few of the more basic plagioclase crystals being cloudy. Pleochroic halos are common in the biotite. The quartz has very little undulatory extinction. A few grains of reticulated quartz contain slender needles of rutile and plates of ilmenite. The plagioclase is oligoclase in composition.

Mode and Chemical Analysis from outer zone granite, Enchanted Rock Batholith
(From R.M. Hutchinson, 1956, Geological Society of America Bulletin)