From DT Online

Lijiang Yunnan Handcrafted-Coppersmith-Works-01

Malleability is the property or physical characteristic of a material (usually metals) to be moulded or formed into shape (e.g. like putty or clay). It can easily be formed by Compressive Forces.

Lead is very Malleable in its normal state but other metals may have to be Annealed first. Gold is normally so Malleable it can be beaten into wafer thin sheets of Gold Leaf whereas Copper, Brass, Aluminium and Silver may have to be Annealed before they can be worked into shape.

Metals which are not Malleable may fracture, break or shatter if they are bent and these are said to be Brittle (e.g. like chalk).