afghs_001. Thin section of the Cape Ann Granite in plane polarized light (ppl). The cloudy gray minerals are alkali felspar (microperthite). The colorless mineral is quartz. The dark green to brown minerals are an iron-rich clinopyroxene (aegirine) and an iron-rich amphibole (arfvedsonite). Zoom in and out with the scroll button or mouse pad. Click on the "LoadHiRes" button if you want a higher resolution image.