Andeite Slab From New Mexico Weighs 4 1/2 Oz and measures about 5.0" x 2.5" x .302" thick or 7.69 mm thick. Not found world wide so looks rare? Richard I have the full story on that green/black rock Bill Langham was one of the 3 who founded the 'Rockmania" rock club in Lordsburg,.. he and his son were ones who brought back a piece of the rock, and decided to send a piece of it to the Smithsonian museum for analysis. they determined that it was serpentine, magnetite, and hemitite of which they had never seen that combination before... so they contacted Bill, and said they needed to assign a name to it.. Bill used his son's name... Andy..... and now you know the rest of the story.