Q: What is gneiss?
A: Gneiss is a type of metamorphic rock.
Q: Where do the minerals in gneiss come from?
A: The minerals in gneiss may come from rocks which were originally either igneous or sedimentary.
Q: How are the minerals in gneiss formed?
A: They were heated and squeezed, and the minerals recrystallized.
Q: What is orthogneiss?
A: Orthogneiss is gneiss obtained from igneous rock (such as granite).
Q: What is paragneiss?
A: Paragneiss is gneiss obtained from sedimentary rock (such as sandstone).
Q: What is the texture of minerals in gneisses?
A: In gneisses, minerals tend to be foliated: layered and segregated into bands.
Q: What is the composition of a mica schist seam?
A: There are seams of quartz and of mica in a mica schist, very thin, but consisting essentially of one mineral.