Zoom in and look at Sample F in detail. This igneous rock contains at least 50% of a dark greenish grey mineral that has been identified as calcium rich plagioclase. There is also about an equal amount of a dark greenish black mineral that forms a texture of interlocking crystals with the plagioclase. Thinking of Bowen's Reaction Series, the dark greenish black mineral would most likely be . a. pyroxene (augite)
b. amphibole (hornblende)
c. biotite
d. muscovite