The color of a fine-grained igneous rock can provide valuable clues about its mineral composition and potentially its formation conditions.
Dark Colors (e.g., black, dark green): These are often associated with minerals like biotite, amphibole, and pyroxene, which are rich in iron and magnesium. Rocks with dark colors are commonly referred to as mafic or basaltic rocks.
Light Colors (e.g., light gray, pink, white): These colors are indicative of minerals like feldspar and quartz, which are common in lighter-colored or felsic rocks. Granite and rhyolite are examples of felsic rocks.