precious greenstone (the color of quetzal feathers) or blue stone (see Molina; Engl. transl. by SW)
Orthographic Variants:
quetzalchalchiuitl
Alonso de Molina:
quetzalchalchiuitl. piedra preciosa de color azul, o verde. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 89r. col. 2. Thanks to Joe Campbell for providing the transcription.