Petrology — if a rock is composed of only one mineral species, what is it called? Choose the best geological term.

Introduction / Context:Rock classification often references both texture and mineralogical composition. Many rocks are mixtures of several minerals; however, some are dominantly a single mineral. Correct terminology is essential for accurate geological description and engineering interpretation of material behavior.

Given Data / Assumptions:

• The rock contains only one mineral species (e.g., limestone as nearly pure calcite, marble as recrystallized calcite, quartzite as almost pure quartz).
• We are choosing a term that reflects mineral count, not texture.
• Standard petrological nomenclature is used.

Concept / Approach:“Monomineralic” literally means composed of one mineral. By contrast, “polymineralic” indicates several minerals. “Homogeneous” describes uniformity, not necessarily single-mineral composition—one can have a homogeneous, fine-grained rock that is still polymineralic. Therefore, the most precise term for single-mineral rocks is monomineralic.

Step-by-Step Solution:

Verification / Alternative check:Common examples include limestone (calcite), dolomite rock (dolomite), quartzite (quartz), and dunite (olivine-dominant), frequently described as monomineralic in texts.

Why Other Options Are Wrong:

• Homogeneous: Could be homogeneous yet polymineralic.
• Non-homogeneous: Opposite of uniform; irrelevant.
• Polymineralic: Implies multiple minerals; contradicts the premise.

Common Pitfalls:Equating visual uniformity with monomineralic composition—microscopic examination may reveal multiple phases.

Final Answer:Monomineralic