Mexico produced this proof bullion coin as part of their Pre-Columbian Tolteca series. This 5 Peso (1 Onza) - 1 Troy Ounce coin has a likeness of a Serpiente Con Craneo (Snake with skull) on the reverse, and the National Arms on the obverse.
Limited mintage of ONLY 4,800 Proofs! Cataloged in Krause as KM#666. NOTE: This is not a black coin but a silver proof (mirror-like) finish.