What is the eco-friendly SANJI teaching chalk?

In our daily life, the most common thing is the teaching chalk. However, due to the different enterprises, there are significant differences in the quality of the produced chalk. So, in the process of choosing export chalk, which chalk can be regarded as eco-friendly teaching chalk?
During the educational process, the most obvious image of the chalk used by teachers is that there is a lot of dust. After teachers finish writing, their clothes and hands are all covered with chalk dust. Therefore, many schools abroad are now seeking the quality of chalk when purchasing it for teachers. This kind of chalk is what we usually call eco-friendly chalk. Because this kind of chalk mainly uses a new type of alternative material in the production process, it not only does not produce dust but also ensures the health of the body. Therefore, teachers do not need to worry about the color not being washed off after using some colored chalk.