You know what pearls are, right? Rare and extremely valuable jewels of the sea. In the Persian Sea, they say you can find black pearls, and a jeweller is looking for one of the highest quality. Any scrap of information will do--can you ask around at Muscat?
The highest quality black pearls shine as beautiful as a peacock's feather. Black pearls of this colour and of a large size sell at prices you wouln't believe. Of course, they're extremely hard to find. If i remember correctly, there were a few baing traded in Basra a few years ago. Maybe you could ask around there?
About five years ago an extremely high quality black pearl came on the market here. Unfortunately, a fight broke out among the many people whose hearts were captivated by its beauty so a wealthy noble bought it and donated it to the mosque to end the people's bickering. I doubt you could buy it now even if you wanted to..
A top grade black pearl was given to the mosque in Basra where it still stay today. I should look around the mosque for future reference. I may not be able to negatoate a deal to purchase it, but i might be able to get some clues.