Warm Lantian, lantian jade, is a famous jade-producing place in the southeast of Lantian, Shaanxi. This mountain is sunny and contains jade gas (the ancients thought that treasures have phosgene invisible to ordinary eyes), and Ran Ran rises. However, although the essence of Meiyu is far away, it is not close, so it is out of reach, representing an extremely beautiful ideal scenery, but it is impossible to grasp and approach.
I found it from someone else's words. You can look at the explanation in the resources, which is particularly comprehensive.