Future research is expected to clear up this issue. H indicates high metallic iron and L indicates low metallic iron. Brecciated meteorites with clasts of more than one type of alteration are designated with the range of alteration present in the meteorite. The letter designation refers to the iron content for the meteorite as a whole. E.g., Zag bears the designation H3-6 .
Principle minerals are bronzite , olivine , and minor oligoclase .
These rare meteorites contain elemental carbon , a basic building block for life. The number refers to alteration. I vuna Friable, more water CI M ighei Friable, less water CM1- CM2 V igarano. Scientists believe that some of these meteorites originated on the surface of the Moon or Mars. 7.8 percent of meteorite falls are achondrites.