Cris's Art Glass House

The key chemical elements for classifying igneous rocks are
A) H, O, C, N
B) Mg, Fe, Si, O
C) Ca, K, Na, Cl
D) Mg, Fe, Al, Si

Igneous rocks that cool slowly, beneath the Earth’s surface are called
A) magmatic
B) plutonic
C) extrusive
D) volcanic

When lava cools so rapidly that the atoms in the magma have no time to form orderly crystals, this forms
A) pyroclastic tephra
B) basalt lava
C) volcanic glass, obsidian
D) granite lava

The size and shape of the grains and the way the grains fit together define the rock’s
A) chemical compound
B) atomic structure
C) texture
D) composition

The types of grains and their appropriate amounts define a rock’s (p.18)
A) texture
B) chemical compound
C) composition
D) atomic structure

Porphyritic texture is common to volcanic rocks and is best described as
A) fine-grained aphanitic
B) med- to coarse-grained phaneritic
C) rocks with both visible and microscopic minerals
D) Coarse-grained minerals