Biotite mica contains iron and/or magnesium, but muscovite mica does not.
Biotite and Muscovite.
Iron is present in biotite mica but not in muscovite mica.
Mica is a group of sheet silicate minerals (e.x of micas : Biotite, muscovite)
Biotite is typically darker in color compared to muscovite, and it has higher iron and magnesium content, which gives it a higher specific gravity. Biotite also exhibits stronger pleochroism compared to muscovite, meaning it shows more noticeable color variations when viewed from different angles. Additionally, biotite has a higher tendency to cleave into thin, flexible sheets compared to muscovite.
The soft silicate flakes found in many rocks are likely to be mica minerals, such as muscovite or biotite. These minerals have a layered structure that allows them to break into thin flakes or sheets easily. Mica minerals are common in igneous, metamorphic, and sedimentary rocks.
Muscovite (clear) and Biotite (black) are the commonest mica forms. Fuchsite (green) is an unusual mica containing chromium. Please see the related link below for a listing of the mica group of minerals.
Mica itself is a mineral resource, and minerals are generally considered non-renewable as they are finite and cannot be replaced on a human timescale. The extraction of mica can also have negative environmental impacts if not managed sustainably.
Mica or silicate
Granite typically contains minerals such as feldspar (including orthoclase and plagioclase), quartz, and mica (including biotite and muscovite). Other minerals like hornblende, amphibole, and pyroxene may also be present in smaller amounts.
Quartz, Potassium Feldspar, Plagioclase Feldspar, Muscovite (mica), Biotite (mica), Amphibole (hornblende), Pyroxene, Olivine, Calcite, Dolomite.
Biotite mica contains iron and/or magnesium, but muscovite mica does not.
Some minerals that have only one direction of cleavage include mica (like muscovite), halite (salt), and graphite. Cleavage is the tendency of minerals to break along preferred planes due to their atomic structure.