As part of classifying an igneous rock, scientists determine its?

Question

a. slilca content
b.extrusive size
c. intrusive size

Answer 1

The size of the intrusion or volcanic flow or layer has nothing to do with rock classification. Therefore determining the silica content (in percent) by analytical methods or microscopy is usually the first step in classifying an igneous rock.

Silica (actually silica dioxide or SiO2) is the main component of a very common group of rock-forming minerals called silicates, including quartz, feldspar, pyroxene, garnet, amphibole, mica...the list goes on and on.

Answer 2

a ***