| "Iron Meteorites: Believed to be the core material from what most likely was another "planetary" type body; (or very large asteroid). The "crust" of that body would be the achondrites. Today, meteoriticists use a new chemical classification system that divides the irons into twelve groups based on the concentrations of trace elements. There are certain elements, the siderophiles, that have an affinity for iron (their atoms can readily bond with iron atoms as the iron crystallizes in a melt). These elements include nickel as the major element and several trace elements such as iridium, gallium, and germanium."
Octahedrites: most iron meteorites contain between 7 percent and 13 percent nickel. This nickel content results in mixtures of low-nickel kamacite and high-nickel taenite. The intergrowth of these two alloys leads to a striking structure that is diagnostic for octahedrites.
Facts and Information from:
Rocks From Space
second edition 1998
O. Richard Norton
Mountain Press Publishing Company
P.O.Box 2399, Missoula, Montana 59806
(406) 728-1900 |
