What is the white crystal on the rockery?

Hello, the white crystal on the rockery is because the calcium bicarbonate in the stone reacts with water to form calcium carbonate, so it adheres to the rockery to form a white crystal. Petrochemical calcium carbonate (slightly soluble in slight acid) and some mountain mud are mixed with slag, and some calcium carbonate with low density and high brittleness is contained. After the bonsai is made, some calcium carbonate crystals will appear on the surface driven by the water flow. The white crystal on the water-absorbing stone is mainly water alkali, and the component is calcium carbonate. At this time, the density and hardness of calcium carbonate are not good, and it is easier to clean. The salt mentioned above reacts with acid to form another compound. Then calcium carbonate can also be decomposed into other compounds with acidic substances. I hope my answer can help you.