Why this rock is probably not a meteorite:

The person who sent this photo (top) identified the light-colored clasts as plagioclase feldspar, the orange spots as orthoclase, and the dark matrix as consisting of pyroxene and olivine. He only claimed that it was an anorthosite (the most common type of plutonic rock on the Moon), not that it was a lunar meteorite.

In lunar meteorites (the regolith breccias), plagioclase clasts occur in a plagioclase-rich matrix, not a mafic (olivine, pyroxene) matrix. Also, the clasts are not so rounded; they're more angular. There would be a lot of small clasts. I'm unaware of any lunar breccias that has such a high proportion of golf-ball-sized clasts.

And, of course, the rock doesn't have a fusion crust. This is a rock that's been rounded by grinding against other rocks in flowing water.
 
What is it?

The rock is a basaltic rock with plagioclase megacrysts. Such rocks occur on Earth. The lower photo is a rock from Greenland. It has plagioclase megacrysts in a hornblende matrix (rock courtesy of Bob Dymek).
   



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