Vesicles

If the rock has a lot of vesicles (gas bubbles, holes), then it is not a meteorite. Nearly all of the photos below were sent to me by people who thought the rocks were meteorites.  Many to most of them rocks below are terrestrial volcanic rocks; some are slags. None have fusion crusts because none is a meteorite.

More information on vesicles in meteorites. (OK, some meteorites do have vesicles, but not as many as in the rocks pictured here.)