Geological classification of marble: From a geological standpoint, marble belongs to which category of rocks?

Introduction / Context:
Accurate rock classification affects expectations about durability, weathering, and workability. Marble is widely used in architecture and sculpture; recognizing its origin informs selection and maintenance decisions.

Given Data / Assumptions:

• Marble results from the transformation of pre-existing rock.
• Recrystallization implies metamorphism.

Concept / Approach:
Marble forms when limestone (a calcareous sedimentary rock) undergoes metamorphism under heat and pressure, causing calcite crystals to recrystallize. Thus, marble is classified as a metamorphic rock, not sedimentary or igneous. “Stratified rock” refers to layered structure typical of many sedimentary rocks; metamorphism often obliterates original bedding.

Step-by-Step Solution:

Verification / Alternative check:
Petrology texts describe coarse interlocking calcite crystals in marble and the loss of fossils/strata typical of limestone due to metamorphism, confirming the metamorphic classification.

Why Other Options Are Wrong:

• Sedimentary: describes limestone, not its metamorphosed form.
• Igneous: formed from magma; not applicable here.
• Stratified: a structural descriptor of many sedimentary rocks, not a metamorphic category.

Common Pitfalls:

• Using commercial trade names (“marble”) for any polishable carbonate rock; geologically, true marble is metamorphic.

Final Answer:
metamorphic rock