Caption: 
A second example of the Chelyabinsk meteorite. This specimen shows a highly developed network of thin impact melt veins (dark lines) and impact melt pockets (dark blobs). The dark material around the outside of the meteorite is not impact melt, but fusion crust created during atmospheric entry; the presence of fusion crust indicates this stone broke away from the main mass during entry. Shiny metallic grains are readily visible.

Credit: 
Image Courtesy of Qingzhu Yin, Univ. California-Davis