What Are Some of the Hardest and Softest Metals?

Lead has a Mohs hardness of just 1.5, making it one of the softer metallic elements that is often encountered. Tungsten has a Mohs hardness of 7.5, making it one of the hardest elements found in metallic compounds. The Mohs scale of hardness assigns a value between one and ten to each substance depending on how easily it can be scratched. It is possible to scrape a material that has a lower Mohs hardness using a substance that has a greater Mohs hardness. The Mohs scale assigns a value of 10 to diamond, making it the hardest material ever discovered.

On the Mohs scale, alkali metals have a tendency to have lower rankings. One example of a material having a Mohs hardness of 0.5 is sodium metal, which can be sliced with a knife. The relative tenacity of the elements lithium, potassium, and rubidium is 0.6, 0.4, and 0.3 correspondingly. The hardness of caesium is 0.2, and it is a liquid at ambient temperature. Caesium has a low melting point. Additionally, noble metals have a propensity to be soft. Both gold and silver have a hardness value of 2.5 on the Mohs scale.

On the other hand, the majority of transition metals have a Mohs scale ranking that is extraordinarily high. The Mohs scale assigns a value of 6.0 to measure the brittleness of titanium, niobium, and rhodium. Tantalum, rhenium, and osmium come in at even higher ranks than that, with respective hardness ratings of 6.5, 7.0, and 7.0. Finally, the hardness of certain metal alloys may go above that of their parent element, as is the case with tungsten carbide, which has a hardness that ranges from 8.5 to 9.0.