Felsite n. : A finegrained rock, flintlike in fracture, consisting essentially of orthoclase feldspar with occasional grains of quartz.

Example:
Which of the 20 minerals are silicates, carbonates, oxides, sulfides, sulfates, are metallic in nature,?

Taxonomy
Felsite, quartz, free encyclopedia, rock, colored rock, fine-grained matrix, search, fine grained, chemical analysis, precise definition, light gray, dark gray, colors, mass, porphyry, phenocrysts, Cornelis, Hurlbut.

Defination from the web:
Felsite is a field term for a light colored rock that typically requires petrographic examination or chemical analysis for more precise definition. ... particularly quartz, sodium and potassium feldspar, and may be termed a quartz felsite or quartz porphyry if the quartz phenocrysts are present. ...