Which of the following minerals is a ferromagnesian silicate? quartz muscovite orthoclase hornblende
The Correct Answer and Explanation is:
Correct Answer: Hornblende
Explanation:
Ferromagnesian silicates are a group of silicate minerals that contain significant amounts of iron (Fe) and magnesium (Mg). These elements give the minerals a dark color, typically black or dark green, and make them denser than non-ferromagnesian silicates.
Let’s briefly examine the given options:
- Quartz:
Quartz is composed of silicon and oxygen (SiO₂). It contains no iron or magnesium, so it is not a ferromagnesian silicate. It is usually colorless or light-colored and is part of the felsic mineral group. - Muscovite:
Muscovite is a type of mica, usually light-colored and rich in potassium and aluminum. It does not contain significant amounts of iron or magnesium, making it non-ferromagnesian. - Orthoclase:
Orthoclase is a potassium feldspar. It is light in color, typically pink, white, or cream. It contains potassium, aluminum, and silicon, but not iron or magnesium, so it is also not ferromagnesian. - Hornblende:
Hornblende is a dark-colored mineral and a member of the amphibole group. It contains a complex mix of elements, including iron (Fe), magnesium (Mg), calcium (Ca), aluminum (Al), silicon (Si), and others. The presence of both iron and magnesium classifies hornblende as a ferromagnesian silicate.
In summary, hornblende is the only option that fits the definition of a ferromagnesian silicate. Its iron and magnesium content, along with its dark color and density, distinguish it from lighter, non-ferromagnesian silicates like quartz, muscovite, and orthoclase.
