Which of the following is a metamorphic rock?

• A. Marble
• B. Granite
• C. Basalt
• D. Sandstone

Answer: (A)

Rocks are grouped by how they form. Metamorphic rocks come from existing rocks that are altered by heat and pressure, which drives mineral changes and new textures without melting. Marble forms when limestone is subjected to metamorphism; the calcite minerals recrystallize into interlocking grains, giving marble its distinctive crystalline texture and often veined appearance. This transformation preserves the rock’s chemistry while changing its structure. In contrast, granite and basalt are igneous rocks created by cooling magma or lava, producing different crystal textures, and sandstone is a sedimentary rock formed from cemented sand grains. So marble is the metamorphic rock.