Luobi Cave Luobi Cave Luobi Cave () is a karst cave under the west face of Yin Ridge (印岭) located north east of Lizhigou Town (荔枝沟镇), from Sanya City, Hainan Province, People's Republic of China. The entrance to the cave is approximately high and wide. Inside the apex reaches a height of with a floor area of about Two large stalactites hang down from the roof like large pens, hence the cave's name. A number of inscriptions carved into the walls of the cave are believed to date to the Yuan Dynasty (1271–1368). One of these refers to the precise date of
Calcium carbonate Alternatively, calcium carbonate is prepared from calcium oxide. Water is added to give calcium hydroxide then carbon dioxide is passed through this solution to precipitate the desired calcium carbonate, referred to in the industry as precipitated calcium carbonate (PCC): The thermodynamically stable form of CaCO under normal conditions is hexagonal β-CaCO, (the mineral calcite). Other forms can be prepared, the denser,(2.83 g/cc) orthorhombic λ-CaCO ( the mineral aragonite) and μ-CaCO, occurring as the mineral vaterite. The aragonite form can be prepared by precipitation at temperatures above 85 °C, the vaterite form can be prepared by precipitation at 60 °C. Calcite