Pallasites are the rarest type of meteorites found. Not only do they contain an iron-nickel metal, they also have crystals of olivine (the yellow/green areas seen in the photo). Each piece of meteorite is different; no two will be the same. The meteorite you receive may not be the one in the picture.
The slice in this necklace is from the Seymchan meteorite that was found in Russia in 1967. The pendant mounting is made from 14K yellow gold.