Why this rock is probably not a meteorite:

If you've gotten this far and have been paying attention, you might be thinking, "That's not a meteorite because there is no fusion crust and the exterior is too rough." (Click on image for enlargement.)
What is it?

This is a meteorite. It was bought from a dealer and it was purported to be a meteorite from the desert of northwest Africa. This is a fragment of a meteorite, with the weathered, broken surface exposed (mm ticks on ruler). The shiny coating is not a fusion crust but desert varnish. Under different lighting (small | big), shiny metal grains appear at the surface. That's the first clue that it is a meteorite. The rock is strongly magnetic. On a sawn surface, many shiny metal grains can be seen (different lighting: small | big). Together these two features suggest that the shiny grains are not some type of oxide or sulfide mineral, but iron metal. The finely and evenly disseminated nature of the metal (unlike no. 011) is exactly what is observed in ordinary chondrites. The large proportion of metal is characteristic of an H chondrite, one of the most common kinds of meteorite. In thin section (0.03 mm thick, 4.5 cm in longest dimension: small | big), the metal looks gray or black. The round, light colored things are chondrules. The reddish minerals are olivine and pyroxene (see also no. 035, which is another H chondrite).


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.