It is a solid, flammable and waxy substance produced in the digestive system of sperm whales and often referred to as "floating gold". It is usually found on the surface of water or deposited on tropical beaches, and is highly valued by the perfume industry who use it to make luxurious perfumes. This waxy, fragrant substance is lighter than water and can drift on the seas for years, where it hardens under the effect of salt water and the sun. When stored in an airtight container, ambergris has a strong musky smell, which is highly appreciated by perfumers around the world, and was used as an aphrodisiac in ancient times. It is one of the most expensive ingredients used in perfumes. The smell of ambergris is characterized by an invigorating musky aroma with oriental touches. Ambergris has long been considered a symbol of luxury.