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Examples of regions with concentrations of alkali feldspar megacrysts without sharp boundaries with adjacent rock. A, C Field photographs showing the plastic film adhered to the rock, prior to tracing. B, D Field photographs after tracing. Note that, in both examples, megacrysts are more abundant than in areas with dispersed megacrysts. Importantly, the number of crystals of a given size decreases with increasing crystal size. Scale in centimeters visible in all photos
