As the fartographer, master of his trade as to be colloquially recognized with the royal THE, was saying, afew years back some NASA intern was caught stealing moon rocks from the Apollo missions and boinkin' some ladies over top of them. Scandalous, but legendary. I can see the appeal
I wish I could ask them if the "clay fibers" present are something you could make a clay pot out of, if you had enough of them.
But I'm not geologist enough to know if the meaning of "clay" in this context is the same as the word in other contexts.
(I don't think there's any reason we should make pots out of space clay. I do think it'd be cool for a sci-fi book to have asteroid-clay pottery as a minor world building detail.)