Photomicrographs of Periclase

Photograph 7-85 Dendritic periclase forming substrate for belite overgrowth (center left). Alite crystals exhibit facial extensions into matrix of very finely microcrystalline aluminate and ferrite. Slowly cooled from high temperature. (S A6703) 

Transmitted, plane-polarized light Field dimensions = 0.21x0.21 mm 

Metallic iron Residual from pyrite cinder (Brown, 1948) 

Iron metal Very strong reducing conditions, lack of air (Gllle and others, 1965) 

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