Granite:
* Feldspar: Primarily potassium feldspar (orthoclase or microcline) and some plagioclase feldspar
* Quartz: Significant amounts of quartz (usually 20-60%)
* Other Minerals: Biotite, muscovite, hornblende (in some cases), and minor amounts of other minerals.
Gabbro:
* Feldspar: Predominantly plagioclase feldspar
* Pyroxene: Abundant pyroxene minerals (augite, hypersthene)
* Other Minerals: Olivine (in some cases), hornblende (in some cases), and minor amounts of other minerals.
Key Differences:
* Quartz: Granite contains significant amounts of quartz, while gabbro does not.
* Feldspar Type: Granite has a higher proportion of potassium feldspar, while gabbro has mainly plagioclase feldspar.
* Pyroxene: Gabbro has abundant pyroxene minerals, while granite does not.
In summary: Granite is rich in quartz and potassium feldspar, while gabbro is rich in plagioclase feldspar and pyroxene. This difference in mineral composition is a key factor in distinguishing these two igneous rocks.
