Meteorites do not “burn.” The outsides have melted, but they have not burned and they do not “look burned.”
The light of a meteor is caused by incandescence – the outside gets so hot that it emits light and glows. The inside of a meteorite does not get hot as it comes through the atmosphere. It may get warm, but not hot enough to alter the inside in any important way, such as melting or changing the mineralogy. More information here.