Pearl diving was an important industry in the United Arab Emirates. Divers would spend months at sea from May to September, diving for over 12 hours per day to depths of around 10 meters to harvest pearls. They traded exclusively in Indian rupees and measurements. Divers lived on boats called sambuks with large crews and brought supplies like rice, flour, goats and dates for energy and vitamin C to last their months-long trips. The most common pearl colors were cream and silver-white, while black pearls were the rarest.