Figure 5A. Close-up of Lucerne Granite showing the four common minerals: A = alkali feldspar; P = plagioclase feldspar; Q = quartz; B = black mica (biotite). Two grains with rapakivi texture are outlined. The one in upper center has an inner grain of older plagioclase with abundant biotite inclusions. The one at lower right has an inner grain of alkali feldspar, which is more common. In both cases, the thin white rind is plagioclase. [Click to hide mineral identifications.]

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Last updated on September 16, 2010

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