Felsic Rocks
* Quartz (SiO2): A very common mineral in felsic rocks, giving them a glassy appearance. It's hard, resistant to weathering, and doesn't react with acid.
* Feldspar (KAlSi3O8, NaAlSi3O8, CaAl2Si2O8): A group of minerals that make up a significant portion of felsic rocks. They are typically white, pink, or gray and have a pearly or glassy luster.
* Muscovite (KAl2(AlSi3O10)(OH)2): A mica mineral that is white or silver-colored, has a pearly luster, and is easily peeled into thin sheets.
* Biotite (K(Mg,Fe)3AlSi3O10(OH)2): Another mica mineral, but this one is dark brown to black and has a shiny, almost metallic luster.
* Amphibole (complex silicate): A group of minerals that are often dark green or black, with a fibrous or prismatic habit.
Mafic Rocks
* Olivine ((Mg,Fe)2SiO4): A greenish mineral that is often found in mafic rocks. It is very dense and has a glassy luster.
* Pyroxene (various silicate compositions): A group of minerals that are usually dark green or black, with a rough texture. They have a distinct crystal shape, often with two cleavages that meet at nearly 90 degrees.
* Amphibole (complex silicate): Also present in mafic rocks, but they are more abundant in intermediate rocks.
* Plagioclase Feldspar (NaAlSi3O8 - CaAl2Si2O8): A type of feldspar that is found in both mafic and intermediate rocks. It is usually white or gray, with a pearly luster.
Key Differences:
* Silicon Content: Felsic rocks are rich in silica (SiO2), while mafic rocks have a lower silica content.
* Mineral Color: Felsic rocks tend to be light-colored, while mafic rocks are dark-colored. This is because the minerals in felsic rocks, like quartz and feldspar, are generally light-colored, while the minerals in mafic rocks, like olivine and pyroxene, are darker.
* Density: Felsic rocks are less dense than mafic rocks because they have a higher percentage of lighter minerals.
Remember: These are just the most common minerals found in felsic and mafic rocks. There can be many variations depending on the specific rock type and its formation conditions.
