The elemental and mineralogical composition of primary rocks is determined by the chemical composition of the volcanic or magmatic flow from which it is formed. Extrusive rocks (such as basalt, rhyolite, andesite and obsidian) and intrusive rocks (such as granite, granodiorite, gabbro and peridotite) contain primary minerals including quartz, feldspar, plagioclase, muscovite, biotite, amphibole, pyroxene and olivine in varying concentrations.[3] Additionally, primary sulfate minerals occur in igneous rocks. Primary sulfate minerals may occur in veins, these minerals include; Hauynite, noselite, barite, anhydrite, gypsum (primary and secondary mineral), celestite, alunite (primary and secondary mineral), creedite, and thaumasite.[4]