1. Mineral Composition:
* Light-colored rocks (felsic): Rich in silica (SiO2), typically containing minerals like quartz, feldspar (especially orthoclase and albite), and mica.
* Dark-colored rocks (mafic): Contain less silica, with minerals like pyroxene, olivine, and amphibole.
2. Chemical Composition:
* Felsic rocks: Higher in sodium, potassium, and aluminum.
* Mafic rocks: Higher in magnesium, iron, and calcium.
3. Density:
* Felsic rocks: Generally less dense due to the lighter elements they contain.
* Mafic rocks: Denser due to the heavier elements they contain.
4. Melting Temperature:
* Felsic rocks: Higher melting temperatures, often formed at deeper levels within the Earth's crust.
* Mafic rocks: Lower melting temperatures, often formed at shallower depths or from volcanic eruptions.
5. Appearance:
* Felsic rocks: Light-colored, often with a pink, white, or gray hue.
* Mafic rocks: Dark-colored, often with a black, dark gray, or greenish hue.
6. Texture:
* Felsic rocks: Often have a granular or porphyritic texture, meaning they contain larger crystals embedded in a finer-grained matrix.
* Mafic rocks: Can have a variety of textures, including granular, porphyritic, or glassy.
7. Examples:
* Felsic rocks: Granite, rhyolite, obsidian
* Mafic rocks: Basalt, gabbro, peridotite
8. Origin:
* Felsic rocks: Often associated with continental crust and tectonic plate collisions.
* Mafic rocks: Often associated with oceanic crust and volcanic activity.
In summary: Light-colored igneous rocks (felsic) are distinguished by their high silica content, lighter minerals, lower density, higher melting temperatures, and association with continental crust. They typically have a light color and granular texture. Dark-colored igneous rocks (mafic) are different in all these aspects, with a lower silica content, heavier minerals, higher density, lower melting temperatures, and association with oceanic crust.
