Ambergris

A precious and rare ingredient found floating in the oceans and on shores. It is naturally expelled by sperm whales, so ethically harvested. Nowadays it’s extremely rare and generally replicated in the lab, with the exception of a few artisanal perfumers who still tincture their own. 

Smelling salty and sea-like musky, Ambergris and related molecules such as Ambroxan are extremely good fixatives in perfumery.