A rock contains only one mineral. It is called
Try it first: pick an option, then read the explanation.
Understanding Rock Composition
This question tests the specific terminology used to describe the mineral content of a rock. Remember, rocks are aggregates of one or more minerals.
Detailed Analysis of the Terms
C. Monomineralic
This is the correct answer. The prefix "mono-" means one. Therefore, a "monomineralic" rock is one that is composed almost entirely of a single mineral. While trace amounts of other minerals might be present, one mineral makes up 90% or more of the rock's volume.
- Examples: Dunite (composed of the mineral olivine), Anorthosite (composed of the mineral plagioclase feldspar), and pure Marble (composed of the mineral calcite).
D. Polymineralic
The prefix "poly-" means many. A "polymineralic" rock is the opposite of monomineralic; it is composed of two or more different minerals. Most common rocks, like granite, are polymineralic.
- Example: Granite is a classic polymineralic rock, containing quartz, feldspar, and mica.
A. Homogeneous
This is a general descriptive term meaning "uniform in composition or character". While a monomineralic rock is typically homogeneous, "homogeneous" is not the specific scientific term for a rock containing only one mineral. A very fine-grained polymineralic rock could also appear homogeneous to the naked eye.
B. Non-homogeneous
This means the composition is not uniform. This would describe most coarse-grained polymineralic rocks where you can easily see the different mineral components.
Monomineralic vs. Polymineralic
| Term | Meaning | Number of Minerals | Example |
|---|---|---|---|
| Monomineralic | "One Mineral" | One | Dunite, pure Marble |
| Polymineralic | "Many Minerals" | Two or more | Granite, Basalt |
Study Tips
- Break Down the Words: The prefixes are the key! Mono = One. Poly = Many.
- Monomineralic = One Mineral Rock.
- Polymineralic = Many Mineral Rock.
- Specific vs. General: Remember that "monomineralic" is the specific, scientific term for the condition, while "homogeneous" is a more general description of appearance.