There is a sapphire Wenchang tower at home, which is broken, but since it is sapphire, why is the section gray? Is it fake?

I'm not sure about the quality of your sapphire, but it shouldn't be obvious from the section, because not only jade, but also other stone sections are not smooth and shiny, and it is normal to be gray.

Only after grinding and polishing will it appear bright, and so will jade. Wool looks no different from ordinary stone.

In addition, as a feng shui thing, it can't be used after being damaged.