Briefly describe how igneous rocks are classified. What will ...

[Bob-Dole]

Briefly describe how igneous rocks are classified.
 
  What will be an ideal response?

Question 2

Which is not a danger associated with volcanic ash?
 
  A) Ash gets caught in jet engines causing them to fail.
  B) Ash can set fire to everything it falls on.
  C) Ash can cause roofs to collapse.
  D) Ash, if exposed to enough heat, can turn back to lava.

[af]

Answer to Question 1

Answer: Composition (minerals present) and texture (crystal size) are used to classify and name igneous rocks. Ultramafic, mafic, intermediate, and felsic are compositional categories for magma and igneous rocks. Light-colored silicate minerals dominate in silica-rich felsic rocks, whereas darker silicate minerals form mafic rocks.

Answer to Question 2

Answer: B