Bowen's Reaction Series includes which mineral as part of the sequence Olivine, Pyroxene, Amphibole, Biotite, Potassium Feldspar, Muscovite, Quartz?

• A. Olivine
• B. Muscovite
• C. Quartz
• D. Potassium Feldspar

Answer: (D)

Bowen's Reaction Series describes how minerals crystallize in order as magma cools, moving from mafic minerals rich in iron and magnesium to felsic minerals rich in silica and alkalis. In the early part of the sequence, minerals like olivine, pyroxene, amphibole, and biotite form as the melt is relatively mafic. As cooling continues and the melt becomes richer in silica and alkalis, the minerals that crystallize later are the felsic ones. Potassium feldspar appears after the early mafic minerals and before the final felsic minerals, muscovite and quartz. This placement reflects its intermediate position in the felsic crystallization path—more silica- and alkali-rich than biotite but forming before the very late-stage minerals. Quartz is typically the last of these minerals to crystallize, with muscovite and potassium feldspar occurring prior to it.