Trade was the most important activity of the Muisca with other Chibcha-speaking neighbours, such as the Guane, Lache and U'wa and with Cariban-speaking groups such as the Muzo or "Emerald People". Their knowledge of salt production from brines, a task devoted exclusively to Muisca women, gave them the name of "Salt People". Tropical fruits that didn't grow on the cool highlands, as well as coca, cotton and gold were all traded at markets that took place every Muisca week; every four days. At these frequent markets, the Muisca obtained various luxury goods that appear worthless in a modern sense, as well as precious metals and gemstones that seem valuable to us and which became abundant and were used for various purposes. The Muisca warrior elite were allowed to wear feathered crowns, from parrots and macaws whose habitat was to the east of the Andes; the Arawkan-speaking Guayupe, Tegua and Achagua.