Building Stones MCQ with answer and solution

Concept

Geological classification of sandstone

Formula

NONE

Step-by-step solution

1. Sandstone is formed by the accumulation, compaction, and cementation of mineral particles or rock fragments over time. 2. Rocks formed through this depositional process are classified as sedimentary rocks. 3. Therefore, sandstone is a sedimentary rock. Answer: A

Explanation

Sandstone is formed by the accumulation, compaction, and cementation of mineral particles or rock fragments, mostly composed of quartz and feldspar. Because these mineral grains deposit in layers over time near the Earth's surface, sandstone is classified as a clastic sedimentary rock.

Why the other options are wrong

B) Metamorphic rocks are formed by the transformation of pre-existing rocks under high heat and pressure. C) Extrusive igneous rocks form from the rapid cooling of lava on the Earth's surface. D) Intrusive igneous rocks form from the slow cooling of magma beneath the Earth's surface.

Shortcut

Sand forms Sedimentary rock ("Sand" = "Sedimentary").

Common mistake

Confusing sandstone with its metamorphic equivalent, quartzite, or classifying it as an igneous rock.