Figure F86. Photomicrograph of thin section from Sample 185-801C-50M-1, 43-45 cm. The groundmass is microcrystalline and is composed of plagioclase, pyroxene, traces of magnetite, and interstitial material. A fracture runs through the center of the photograph and is filled on one side by sulfide (S) and on the other by chalcedony (C). Secondary sulfides are also found in the groundmass near the fracture.