Floating Gold ? A Natural (and Unnatural) History of Ambergris : University of Chicago Press : 9780226821054 : 0226821056 : 13 Sep 2022 : A fascinating natural history of an incredibly curious substance. ?Preternaturally hardened whale dung? is not the first image that comes to mind when we think of perfume, otherwise a symbol of glamour and allure. But the key ingredient that makes the sophisticated scent linger on the skin is precisely this bizarre digestive by-product?ambergris. Despite being one of the world's most expensive substances (its value is nearly that of gold and has at times in history been triple it), ambergris is also one of the world's least known. But with this unusual and highly alluring book, Christopher Kemp promises to change that by uncovering the unique history of ambergris. A rare secretion produced only by sperm whales, which have a fondness for squid but an inability to digest their beaks, ambergris is expelled at sea and floats on ocean currents for years