Growth of calcium carbonate crystal imitating stalagmite growth in nature

Calcite crystals were prepared by dropping a saturated calcium carbonate aqueous solution on a substrate. The calcite crystals were grown with a growth rate of approximately 0.7 μm/day under the condition of aqueous temperature of 2 °C, aqueous concentration of 0.006 mol/l, and substrate temperature of 40 °C. When the calcite substrate was used, calcite crystals were grown epitaxially. Na2CO3 and CaCl2 aqueous solutions were dropped and reacted on the calcite crystal substrate with a CaCO3 concentration of 0.06 mol/l, which is 10 times the saturated concentration at an aqueous temperature of 40 °C. Rhombohedral calcite was also deposited epitaxially with a growth rate of about 6.3 μm/day under this condition.