Malleable minerals are those which can be hammered flat without falling to powder. Some native metals, like gold, silver and copper, are malleable. Sectile minerals, on the contrary, will be demolished if hammered, but will not powder if cut with a knife. Gypsum is a sectile mineral. Minerals that can be attracted by a common horseshoe or bar magnet are magnetic minerals.
Hundreds are magnetic after being heated or tested with an electromagnet.
Only two common minerals, magnetite and pyrrhotite, can be picked up before such treatment. Some minerals possess a property that causes them to glow. When fluorescent minerals are exposed to invisible radiations, such as ultraviolet light, X-rays, and cathode rays, they will glow in the dark. Even after the lamp is turned off though, some minerals tend to continue glowing. They are described as phosphorescent .