Tetrataenite is an ULTRA-RARE, EXTRATERRESTRIAL iron nickel alloy, found ONLY meteorites. On the evening of December 15, 1978 a bright fireball was observed traveling over North Central Mexico. It exploded, raining down hundreds of small black stony meteorites into the desert and ranches near the small town of Nuevo Mercurio, Zacatecas. It is classified as an H5 chondrite and the sawed slab is very RICH in silvery-bright tetrataenite crystals.