Greetings Bernd, Mike, List: --- tett <[EMAIL PROTECTED]> wrote: > How can you tell the difference between kamacite and > taenite? Does the crystal structure give it away?
So far as I can remember... Taenite (79.19 % Fe 20.81 % Ni) aka gamma-iron and kamacite (89.54 % Fe 10.46 % Ni)aka alpha-iron, are the two iron-nickel minerals responsible for Widmanstaaten patterns. While they differ in molecular composition they both have an isometric-hexoctrohedral crystal lattice. It is the packing of the nickel within the lattices which make the distinction. Face loading vs Center loading (which I shan't go into the whys here-check the archives) makes more spaces to put nickel atoms into a molecule. Nickel is more resistant to the acid etching/weathering. Therefore, the taenite lattice will stick out from the surface in higher relief than the kamacite lattice, and that is the only way to "visually" distinguish them from each other in normal nickle-iron faces. Elton ______________________________________________ Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
