Sectility
Sectility is the ability of a mineral to be cut into thin pieces with a knife. Minerals that are not sectile will be broken into rougher pieces when cut. Metals and paper are sectile.
Sectility can be used to distinguish minerals of similar appearance, and is a form of tenacity. For example, gold is sectile but pyrite is not.
Sectility in metals is a result of metallic bonding, where valence electrons are delocalized and can flow freely between atoms, rather than being shared between specific pairs or groups of atoms, as in covalent bonding.
