Choc Fill in the blanks to complete these sentences about rock characteristics. A rock is an of minerals. The of a rock is a result of its mineral composition. Most rocks contain more than one type of
The Correct Answer and Explanation is:
Correct Answer:
A rock is an aggregate of minerals. The color of a rock is a result of its mineral composition. Most rocks contain more than one type of mineral.
Explanation: The Nature of Rocks
In geology, a rock is formally defined as a naturally occurring solid aggregate of one or more minerals or mineraloids. The term “aggregate” is key, as it signifies that a rock is a cohesive mass composed of individual mineral grains that have been cemented or interlocked together. These minerals are the fundamental building blocks of all rocks and, by extension, the Earth’s crust.
The vast majority of rocks are polymineralic, meaning they contain more than one type of mineral. A common example is granite, an igneous rock easily identified by its mixture of interlocking crystals, primarily light-colored quartz and feldspar and dark-colored biotite mica or hornblende. In contrast, a few rocks, known as monomineralic rocks, are composed almost exclusively of a single mineral. For instance, marble is made of calcite, and quartzite is made of quartz. However, these are less common than their polymineralic counterparts.
The properties of a rock are a direct reflection of its components. A rock’s mineral composition—that is, the specific types of minerals it contains and their relative proportions—determines many of its physical characteristics. Among the most immediately observable of these is color. The overall hue of a rock is a composite of the colors of its constituent minerals. Rocks rich in light-colored minerals like quartz and feldspar (felsic minerals) tend to be light gray, white, or pink. Conversely, rocks rich in dark, iron- and magnesium-heavy minerals like pyroxene, amphibole, and olivine (mafic minerals) are typically dark green, gray, or black. Therefore, color serves as an important initial clue for geologists in identifying a rock and deciphering its origin.thumb_upthumb_down
