SEM images of the precipitates from Spring #1 (a,b) and Spring #2 (c,d). (a) The carbonate surface film from Fig. 1a, sample OM01: rhombohedral calcite in a network of aragonite needles. (b) Sample OM03, dypingite rosettes (black arrow) surrounded by acicular aragonite; (c) Sample OM08 from Fig. 1b, crystals of aragonite; (d) close-up of the same area showing a secondary phase (black arrows) growing from or nucleating on the aragonite crystals. These crystals are probably dypingite. Samples OM03 and OM08 were collected from the bottom of the springs.