A felsic plutonic rock would be characterized by being:

• A. Dark-colored with small crystals.
• B. Light-colored with large crystalline regions.
• C. Layered bands of minerals.
• D. Glassy and uniform color.

Answer: (B)

Felsic plutonic rocks form deep underground and cool slowly, so their minerals have time to grow into visible crystals. This makes them light-colored overall because they’re rich in light-colored minerals like feldspar and quartz, and their texture is coarse-grained with large crystalline regions. That combination—light color plus large crystals grown in a slowly cooling environment underground—is the hallmark of felsic plutonic rocks.

For comparison: dark-colored rocks with small crystals point to mafic rocks that cooled quickly at or near the surface, yielding a fine-grained texture. Layered bands of minerals indicate metamorphic processes that produce foliation or banding, not a single igneous texture. Glassy, uniform color describes volcanic glass formed by rapid cooling on the surface, which lacks the crystalline structure seen in plutonic rocks. Granite is a classic example of a felsic plutonic rock, illustrating the light color and coarse crystals characteristic of this group.