Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Surface of the fracture of element 3b. Fracture with visible so-called chevron marks, beginning from the area of the crack’s initiation (a). Additionally, visible plastic deformations of the surface forming its characteristic wrinkling (b). Stereoscopic microscopy.
