Why this rock is not a meteorite:

Well, now, this is annoying. Right now (Nov 12, 2007) there's a guy who's trying to sell 7 rock pieces on e-bay as lunar meteorites. He has the nerve to use diagrams from MY web site on lunar meteorite compositions to add credence to his claim that the rocks are meteorites from the Moon. (This is the same guy who tried to sell no. 223 as a mesosiderite.)

The ads make the logical error of showing that the composition* of the alleged lunar meteorites does indeed plot on the trend of lunar meteorites on ONE of the plots I use to classify lunar meteorites, Al2O3 vs FeO+MgO (or Al2O3 vs. Fe2O3). However, the composition falls far off the trends for MgO/FeO (=0.15), Fe2O3/MnO (=23), K2O (=1.27%), and Cr (138.8 ppm Cr2O3 = 95 ppm Cr). This as a great example of selective validation. As I say on my "Chemical Composition of Meteorites" web site, "If you have a meteorite, its composition must be consistent with ALL of the chemical-composition parameters shown here, not just some of them!"

By the way, the photo on the right is one I lifted from the e-bay ad and "improved."  

* "SiO2 49.27% AL2O3 17.38% FeO 18.83% MgO 2.84% Na 0.94% P2O5 0.50% SO2 0.30% K2O 1.27% CaO 6.17% TiO 0.95% MnO 0.84% ... Cr2O3 138.8 ppm CoO 847.6 ppm NiO 197.9 ppm..."
 
What is it?

Hard to say. With 17.38% Al2O3, it's not an olivine gabbro, as claimed in the ads.
  

www.catchafallingstar.com
www.catchafallingstar.com


Prepared by:

Randy L. Korotev


Department of Earth and Planetary Sciences
Washington University in St. Louis


Please don't contact me about the meteorite you think you’ve found until you read this and this.

e-mailkorotev@wustl.edu