Calcite tubule

Figure 10. (left) Photograph of a flowery exudation of sulfur on concrete immersed in distilled water for 10 months. The basal mound of sulfur crystals is surmounted by a sulfur bloom grown at the tip of a calcite tubule (Magnification X8). (right) Liquid extrusions on dried concrete surface adjacent to earlier sulfur exudation. Same scale. 

Figure 11. Scanning electron micrographs of a calcite tubule, (left) pro-truding from surface of concrete in a mass of sulfur crystals (X44) (right) showing crystal growth in the walls and striae in the conduit (X440)...

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