The fractured surface of "Shanliu" hasn't been fully ground and appears with a fibrous blast-like texture; whereas the fractured surface of Gobi material has been almost entirely smoothed, showing round-bottomed凹pits formed by impacts.
The analytical principle is not difficult to understand: "Shanliu" represents the state of mountain material that has just begun to be worn after being peeled off from the ore body, with incomplete wear; while Gobi material has not only experienced full wear but also endured the harsh tests of sandstorms on the Gobi desert, truly weathered through time. Generally, Gobi material is not easy to process, and sometimes carving it doesn't hold much significance. Just placing it as it is, preserving the craftsmanship of nature, can be meaningful - like the piece below titled "Steadfast in Power."