Which among the following occur as fine-grained rocks?
(A) Rhyolite (B) Diorite (C) Gabbro (D) Andesite (E) Basalt
Choose the correct answer from the options given below:

Correct option is C

Fine-grained rocks are igneous rocks that cool rapidly, typically at or near the Earth's surface. This rapid cooling prevents large crystals from forming, resulting in fine-grained or aphanitic textures. Let’s analyze the given options:
1. Rhyolite (A):
· Fine-grained extrusive igneous rock, formed from rapid cooling of felsic lava.
2. Diorite (B):
· Coarse-grained intrusive igneous rock, formed from slow cooling of intermediate magma.
3. Gabbro (C):
· Coarse-grained intrusive igneous rock, formed from slow cooling of mafic magma.
4. Andesite (D):
· Fine-grained extrusive igneous rock, formed from intermediate lava.
5. Basalt (E):
· Fine-grained extrusive igneous rock, formed from rapid cooling of mafic lava.
Thus, the fine-grained rocks are Rhyolite (A), Andesite (D), and Basalt (E), making the correct answer (c) (A), (D), and (E) only.
Information Booster: 1. Fine-Grained Igneous Rocks:
· Formed from rapid cooling at the surface (extrusive rocks).
· Examples: Rhyolite, Andesite, Basalt.
2. Coarse-Grained Igneous Rocks:
· Formed from slow cooling beneath the surface (intrusive rocks).
· Examples: Diorite, Gabbro, Granite.
3. Textures of Igneous Rocks:
· Aphanitic (fine-grained): Small, indistinguishable crystals.
· Phaneritic (coarse-grained): Large, visible crystals.
4. Key Differences:
· Extrusive rocks cool quickly and are fine-grained.
· Intrusive rocks cool slowly and are coarse-grained.
Additional Knowledge: Rhyolite (A):
· Felsic extrusive rock, fine-grained equivalent of granite.
Diorite (B):
· Intermediate intrusive rock, coarse-grained equivalent of andesite.
Gabbro (C):
· Mafic intrusive rock, coarse-grained equivalent of basalt.
Andesite (D):
· Intermediate extrusive rock, fine-grained equivalent of diorite.
Basalt (E):
· Mafic extrusive rock, most abundant fine-grained igneous rock on Earth.