English: Illustration of "coatli" (lignum nephriticum) by Spanish Franciscan missionary and ethnographer Bernardino de Sahagún in the Florentine Codex. He describes its unusual property of turning the color of water that comes in contact with it to bright blue: "...patli, yoan aqujxtiloni, matlatic iniayo axixpatli (...it is a medicine, and makes the water of blue color, its juice is medicinal for the urine)"