Which mineral is last in the Bowen's sequence Olivine, Pyroxene, Amphibole, Biotite, Potassium Feldspar, Muscovite, Quartz?

• A. Olivine
• B. Muscovite
• C. Quartz
• D. Biotite

Answer: (C)

In a cooling silicate melt, minerals crystallize in order of decreasing temperature. Early-formed minerals (olivine, followed by pyroxene, amphibole, and biotite) remove Mg, Fe, and other elements, leaving a melt that becomes richer in silica and alkalis. As cooling continues, felsic minerals form in sequence: potassium feldspar appears before muscovite. When the melt becomes highly silica-saturated and depleted of most other components, quartz—pure SiO2—crystallizes. Because quartz requires a very silica-rich environment and low concentrations of other elements, it crystallizes last. That’s why quartz is the final mineral in the Bowen sequence.