Lithium be cut with a knife. When cut, it possesses a silvery-white color that quickly changes to gray as it oxidizes to lithium oxide. While it has one of the lowest melting points among all metals (180 °C), it has the highest melting and boiling points of the alkali metals. Lithium has a very low density (0.534 g/cm), comparable with pine wood. It is the least dense of all elements that are solids at room temperature; the next lightest solid element (potassium, at 0.862 g/cm) is more than 60% denser. Furthermore, apart from helium and hydrogen, it is less dense than
Type 72 non-metallic anti-tank mine of the its low metal content, the Type 72 cannot be located using metal detectors under most field conditions. The Type 72 is resistant to shock and overpressure from explosive breaching systems such as the Giant Viper and MICLIC. A copy of the mine, the YM-III (sometimes YM-3), is produced in Iran. It is slightly heavier at 7 kg, with a slightly heavier 5.7 kg Composition B main charge, with a slightly higher activation pressure of 450 to 900 kg. Additionally, a copy is produced in South Africa as "Non-metallic anti-tank mine". Type 72 non-metallic anti-tank mine Type 72 Non-Metallic