As a mineralogist, it is important to be able to tell the difference between pyroxene and amphibole. Both of these minerals are found in rocks, but they have different properties that set them apart. This blog post will discuss the differences between these two minerals, so you can be sure to identify them correctly.
What is Pyroxene?
- Pyroxene is a type of rock-forming mineral found in many igneous and metamorphic rocks. Pyroxenes are characterized by their distinct prismatic or plate-like shapes, and they can range in color from white to dark greenish-black.
- The most common pyroxenes include enstatite and augite, although there are many other varieties of this mineral. Pyroxenes are important minerals because they can provide information about the composition and history of the rocks in which they are found.
- For example, the presence of certain types of pyroxene can indicate that rock was formed from magma that cooled quickly at high temperatures. Pyroxenes can also be used to date rocks, as some types of this mineral are known to change over time into other minerals. Consequently, pyroxenes are an important tool for geologists who study the Earth’s rocks and minerals.
What is Amphibole?
Amphibole is a group of inorganic minerals that have similar chemical compositions and crystal structures. Amphiboles are found in a wide variety of rock types, including igneous, metamorphic, and sedimentary rocks. The most common Amphibole minerals are hornblende and actinolite. Amphiboles are typically dark-colored and have a fibrous or needle-like structure. This gives them a high degree of cleavage, which means that they can easily be split into thin sheets. As a result, Amphibole minerals are often used for making decorative objects such as vases and bowls. Amphiboles are also an important source of asbestos, which is used in insulation and fireproofing materials.
Differences between Pyroxene and Amphibole
- Pyroxene and amphibole are two groups of rock-forming inosilicate minerals that have similar compositions but distinct crystal structures. Pyroxenes are monoclinic, meaning they have one three-axial crystallographic plane, while amphiboles are orthorhombic, meaning they have three two-axial crystallographic planes.
- Pyroxenes typically have densities of 2.6-3.8 g/cm3, while amphiboles tend to be slightly lighter at 2.5-3.7 g/cm3. Pyroxenes are also generally less refractive than amphiboles, with an index of refraction (RI) range of 1.58-1.65 compared to an RI range of 1.62-1.72 for amphiboles.
- Finally, pyroxenes tend to be darker in color than amphiboles, with a black-to-dark greenish-brown hue, while amphiboles can be brown, green, or even white in color. While both pyroxene and amphibole minerals are found in a variety of igneous, metamorphic, and sedimentary rocks, their distinct properties make them easy to distinguish from one another.
Conclusion
Amphibole and pyroxene are both important minerals, but they have different properties. It is important to know the difference between them so that you can identify them correctly.
