Brown is the second best grade of ambergris and is coveted for a stronger scent than white. For these purposes it is best used for its scent on its own rather than for use as a fixative.
Ambergris is astonishingly rare and spends years if not decades floating out at sea being degraded by the sun and the elements after being expunged from sperm whales.
It is collected from shore after washing up from sea having being out at sea all those years, and is often found after storms and bad weather. Ambergris is perhaps rarer than gold, and is continuously faked, after all to the untrained eye, any similar looking objects washing ashore look the same.
Much of the "ambergris" you will see being sold cheaper online is fake, there are plenty of folk looking to cash in on their beach finds, selling products such as fats from palm oil or other waxes.
The word Ambergris originates from an Old Arabic word 'anbar', having been introduced to the west by the Arabs, it has since played a key role in perfumery across the world both traditional and contemporary.
The early Muslims highly regarded Ambergris from the Coasts of India, with Yemeni Ambergris also highly coveted from Al-Shihr.
The polymath historian Al Masudi lists Ambergris as one of the five principal aromatics (usul al-tib), and it plays a central role in the creation of the renowned and historical fragrant compound - Ghaliyah.