Ma Yadong is also called calcite. The English name of calcite comes from Latin, which means "lime". Chemical composition calcium carbonate is the main component of "sedimentary carbonate rock" and can be dissolved in acidic solution; Tripartite crystal system; Colorless or milky white, if it contains impurities, it can be dyed in many colors; Opaque or translucent; Glass luster; Mohs hardness 3; Specific gravity 2.6-2.8; Diamond cleavage is complete, belonging to a "low-grade" gem, which can be produced in various geological processes, so it is widely distributed. China is one of the top five countries (France, USA, Iceland and Britain) that produce high-quality calcite, most of which comes from "karst" and "endogenetic hydrothermal deposits". Its formation process is that the ore-bearing "gasification-hydrothermal solution" flows in various rock cracks and holes, and accumulates and precipitates into deposits due to the change of "physical and chemical" conditions caused by temperature, pressure and interaction with surrounding rocks. Calcite crystals in central Guizhou are complex triangular rhomboid or rhomboid; Aggregates are granular, bell-shaped, spring-shaped and crystal clusters; Usually no fat, or milky white. There are two varieties of it: one is "measuring stones with ice", which is more than that in caves, forming beautiful and huge crystals, colorless, transparent or golden yellow, with obvious "birefringence" phenomenon; The second is aragonite, which is also the dominant stone and a variety of calcite.