The Tourmaline Brotherhood is a powerful merchant guild within Qarth. It battles for prominence in the city with the Thirteen, the Ancient Guild of Spicers and the Pureborn. The Brotherhood owns approximately eight hundred ships. According to Xaro Xhoan Daxos the Brotherhood is full of pirates.
A Clash of Kings
The Tourmaline Brotherhood gave Daenerys Targaryen a crown wrought in the shape of a three-headed dragon. The coils are made of yellow gold, the wings are made of silver, the heads made of jade, ivory and onyx. After the destruction of the House of the Undying, the Brotherhood called openly for Daenerys's expulsion from the city.