Silicon and germanium are of considerable technological and scientific interest. When subjected to sufficiently high hydrostatic and non-hydrostatic pressures these materials undergo structural phase transitions. As regards the amorphous films of silicon and germanium, the amorphous to crystalline phases transition was reported recently [...].
A meaningful experiment, coming back to the seventeenth century, revealing the internal stresses in a glass drop. A few frames extracted from a movie film by Hervé Arribart and René Gy (Saint Gobain Research).
See also: S. Chandrasekar and M. Chaudhri, Philosoph. Mag. (1994), 70, 1195-1218.