Freshly produced ambergris has a marine, fecal odor. However, as it ages, it acquires a sweet, earthy scent commonly likened to the fragrance of rubbing alcohol without the vaporous chemical astringency. The principal historical use of ambergris was as a fixative, normally the base note in perfumery, though it has now been largely displaced by synthetics.
Perfume is described in a musical metaphor as having three sets of notes, making the harmonious scent accord. The notes unfold over time, with the immediate impression of the top note leading to the deeper middle notes, and the base notes gradually appearing as the final stage. These notes are created carefully with knowledge of the evaporation process of the perfume.
- Top notes: The scents that are perceived immediately on application of a perfume. Top notes consist of small, light molecules that evaporate quickly. They form a person's initial impression of a perfume and thus are very important in the selling of a perfume. Also called the head notes.
- Middle notes: The scent of a perfume that emerges just prior to when the top notes dissipate. The middle note compounds form the "heart" or main body of a perfume and act to mask the often unpleasant initial impression of base notes, which become more pleasant with time. They are also called the heart notes.
- Base notes: The scent of a perfume that appears close to the departure of the middle notes. The base and middle notes together are the main theme of a perfume. Base notes bring depth and solidity to a perfume. Compounds of this class of scents are typically rich and "deep" and are usually not perceived until 30 minutes after application.
The best ambergris goes for $10,000 per pound. A beachcomber in UK just recently found a piece of ambergris worth of $100,000.