Rock-forming minerals – matching common names and properties Which of the following statements about hornblende, muscovite, and biotite is correct?

Introduction:
Minerals such as hornblende and the micas (muscovite and biotite) occur widely in igneous and metamorphic rocks used as construction stone and aggregates. Identifying their common names and basic properties aids in geological classification and in anticipating behavior such as cleavage and durability.

Given Data / Assumptions:

• We compare three minerals and their commonly cited properties/names.
• Focus is on standard descriptive mineralogy used in civil engineering contexts.

Concept / Approach:

Hornblende (an amphibole) is typically brittle with prismatic cleavage. Muscovite is the light-colored mica, often called white mica or potash mica because of its potassium content. Biotite is the dark mica, commonly called black mica. Each statement provided is a conventional fact in introductory mineralogy.

Step-by-Step Solution:

Verification / Alternative check:

Standard mineral tables consistently list these synonyms and physical properties, reaffirming that each individual statement holds.

Why Other Options Are Wrong:

Any single-choice option would omit other true statements; only the combined option captures all truths.

Common Pitfalls:

Confusing amphiboles (hornblende) with pyroxenes; mixing up muscovite and biotite based on color; forgetting that potash mica refers to muscovite due to potassium content.

Final Answer:

All of the above