GlassIf it is glass or glassy, then it is not a meteorite back to “Some Meteorite Realities” If it is brightly colored glass, then it is man-made. These rocks are all obsidian, a volcanic glass that is typically black. Glass, chert, and some fine-grained crystalline rocks fracture conchoidally, too. If there are conchoidal fractures, then it is not a meteorite. back to “Some Meteorite Realities”