Figure 9. Botryoidal calcite filling a cavity in a chlorite-filled vein, Sample 149-899B-20R-2, 16-20 cm. A. Plane-polarized light photomicrograph. Chlorite displays an unusual botryoidal and isotropic habit near the margins of the vein, as evidenced by fine, concentric banding; crystal size is observed to coarsen toward the center of the vein (not shown). Chlorite also occurs in a planar habit at the lower left, crosscutting the botryoidal phase; parallel, high-relief bands that occur in this zone, as well as near the vein walls, may be composed of authigenic smectite. The infilling calcite apparently postdates the chlorite. B. Interpretive sketch of the same view.