From a geological point of view, gems generally belong to minerals, and jade mostly belongs to rocks. There are thousands of rocks on the earth, but only a dozen rocks with beautiful colors and fine texture can be used as jade. To appreciate jade, you must first understand jade. Xu Shen said in Han Dynasty that "jade is the beauty of stone". Generally speaking, beautiful stones that are naturally generated and can become delicate, smooth, colorful, strong and wear-resistant after processing can be classified as jade.