Ambergris

Ambergris, ambergrease, or grey amber is a solid, waxy, flammable substance of a dull grey or blackish colour produced in the digestive system of sperm whales. Freshly produced ambergris has a marine, faecal odour. It acquires a sweet, earthy scent as it ages, commonly likened to the fragrance of isopropyl alcohol without the vaporous chemical astringency.