A waxy substance that originates as a secretion in whale intestines...

I'm talking about ambergris, of course.  At the end of chapter 91 when Stubb sort of cons the French ship out of their whale carcass, he mines the ambergris which is used to make perfumes.  My first thought was, "Is this for real?" When I looked this up online, it was commonly referred to as "whale vomit."  Which made me very interested to get a look.  Here are some pictures that I found:  

So yes, it is for real and still valuable.