What color is the mantle?

Excuse me, but could you please clarify something for me? I've been reading this paragraph and it mentions a mantle, but it doesn't specify its color. I'm really curious to know, what color is the mantle described in the text? It seems like an important detail that could add to my understanding of the overall narrative. Would you mind enlightening me on this matter? It would be greatly appreciated if you could provide a brief description or even hint at the possible hue of this mantle. Thank you in advance for your assistance.