Why this rock is probably not a meteorite:

This is a sawn face of a large rock. The round things could be chondrules in a chondritic meteorite, but they're probably not. First, the specific gravity of the rock, 2.8, is too low for a chondrite. Second, chondrules are not usually this big. Third, chondrules don't have rims like this. Fourth, there's no metal, so it's not an ordinary chondrite; it would have to be a type of rare chondrite. Finally, the matrix is too fine-grained for any type of chondrite (see Allende photos here).
What is it?

This sample is a piece of a pickup-truck-sized rock found in northeast Missouri. We were so fascinated by the texture that we had a petrographic thin section prepared. We think this was a basalt with olivine phenocrysts that has been hydrothermally altered (very hot water). It's probably from the northern Midwest or Ontario and was transported to Missouri by glaciers.


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.