How to distinguish the quality of Hetian jade, mountain material, seed material, goose material and so on?

Hetian jade is still poor, mainly according to density, water head, purity and whiteness, to judge its quality, grade and mountain material; The appearance is irregular, angular and massive, the texture is mostly rough, and the yin and yang sides are obvious. The internal structure clearly shows different jade attributes, but the information is opposite, which has the greatest characteristics of Hetian jade.