How to tell if you've struck gold with ambergris 🐋 Dubbed the ‘treasure of the sea’, ambergris is a rare and valuable substance produced in the colon of sperm whales. It’s believed to help prevent irritation of the lining caused by indigestible squid beaks. Small pieces may be passed through and found floating on water, while larger pieces remain in the colon until the whale dies. The largest piece ever retrieved from a sperm whale weighed nearly half a tonne! You can test for ambergris using t