Figure F39. Photomicrographs showing the presence of Cr spinel inclusions (dark equant crystals) in an altered olivine phenocryst with an iddingsite rim in Unit 6 (Sample 197-1206A-16R-5 [Piece 8, 66-67 cm]) (field of view = 0.625 mm) A. Plane-polarized light; photomicrograph 1206A-372. B. Reflected light; photomicrograph 1206A-371.