Figure 3

(a.) Reflected plane polarized light photomicrograph of specular hematite inclusions in sieve-texture pyrite in hematite-bearing ore from the Bingham North Ore Shoot. Note how hematite blades are rounded and resorbed. The highly irregular black holes in pyrite are of uncertain origin (probably aggregates of minerals that have since been leached or plucked from the sample). Silver blades = hematite, pale yellow = pyrite, yellow = chalcopyrite, black = hole. Width of field = 1.35 mm.

(b.) Reflected plane-polarized light photomicrograph of specular hematite inclusions in sieve-texture pyrite in B-bed ore from the Superior district, Arizona. Note how hematite blades are rounded and resorbed. Chalcopyrite vein cross-cuts pyrite. The non-opaque gangue in this sample is quartz. Silver blades = hematite, pale yellow = pyrite, yellow = chalcopyrite, black = hole. Width of field = 1.35 mm.
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