If it is rectangular or square, then it is not a meteorite

For small meteoroids, 90% of the mass is lost to ablation as they come through Earth’s atmosphere. Edges and corners are the first parts to ablate away. Put an ice cube in water and wait for 90% to melt. The “cube” that remains will have no edges, points, or straight lines. It is like that with meteorites. As a consequence, most stony meteorites have rounded and smooth exteriors, except where they have broken.

Having said that, one can purchase meteorites with flat faces that have been cut with a saw and polished by sellers. One can even purchase meteorites that have been cut into cubes or spheres. As I say elsewhere, however, if the fusion crust has been cut or abraded away, the stone may not easily identified as a meteorite.

All of the photos below were sent to me by persons inquiring whether the object was a meteorite. None of them are meteorites. Nearly all have flat, straight sides or edges. “Flat” and “straight” do not happen naturally in meteorites. Note that none of these rocks has a fusion crust.