quetzalitztli.

Headword: 
quetzalitztli.
Principal English Translation: 

an "emerald" (see Molina), or a type of greenstone or a green obsidian blade, given that -itztli refers to obsidian blades and they have have a gray or a green tint (SW)

Orthographic Variants: 
quetzaliztli
Alonso de Molina: 

quetzalitztli. esmeralda.
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.