Rock with only feldspar and quartz?

what would be the name of an intrusive igneous rock with only quartz and feldspar? My geology teacher didn’t have a clue

rock man,

The most probable answer to your question is granite, but there are several other categories of rock (that need only contain quartz and feldspars) that are considerably less common. It depends on the relative amounts of quartz, alkali feldspar, and plagioclase feldspar. If you click the link below and find your rock’s approximate composition on the upper half of the diagram, you can get a geologically exact answer to your question:

http://en.wikipedia.org/wiki/QAPF_diagram

Another possible answer is pegmatite. A pegmatite is a granitic rock that crystallized very slowly inside the earth and formed large crystals. It is more of a textural term, and is used when the crystal size is quite large. Because these minerals are the last to crystallize, the cores of pegmatites often contain only quartz and feldspar.

Due’le quartz Rock On 2001in Hong Kong-part 1