Hardness

• Harness is determined by a variety of factors. While there are numerous scaling systems used to determine the hardness of a substance, two widely known rating systems are the Mohs scale and Rockwell scale. The testing protocols of either scale can be rendered on almost every solid substance. However, Mohs is primarily used to measure the hardness of minerals and Rockwell is predominately used for metals.
  
  

Non-Metals: Mohs Scale

• The Mohs scale determines hardness by a substance's scratch resistance. On the Mohs scale of one to 10, with 10 being the hardest, titanium rates six. Substances that are harder than titanium on the Mohs scale include sapphire, which ranks a nine and diamond at 10.
  
  

Sapphire

• A corundum is a mineral made of aluminum oxide and is found in various kinds of rocks. A sapphire is a crystallized, transparent corundum, and it is the world's second-hardest natural, non-metallic substance. Even though the most widely known sapphire color is blue, sapphires come in a wide range of colors such as pink, yellow, purple and orange. Considered to be a precious gemstone, sapphires are primarily found in India, Thailand, Sri Lanka, Myanmar, the United States and Australia.
  
  

Diamond

• Diamonds are the hardest known natural substances on Earth. They are made of crystallized, densely concentrated chains of carbon atoms and are found in igneous rock called kimberlite. In addition to their unsurpassed natural hardness, diamonds are superior conductors of electricity and have a high level of refractability. These precious gemstones are thought to have been discovered approximately 6,000 years ago in India. Today they are mined throughout the world, including in Africa, Brazil, the United States, Russia and Siberia. The term "diamond" was derived from the Greek word "adamas," which means unconquerable or invincible
  
  

Metals: Rockwell Scale

• The Rockwell scale determines hardness according to a substance's ability to withstand indentation when certain types of pressures are applied. Rockwell offers three types of testing applications, including one called the "C Scale." On this scale, the higher the number, the greater the hardness level. While pure, organic forms of titanium rate at C24 to 36, maraging steel is C45 to 55 and tungsten carbide is C66.
  
  

Maraging Steel

• Maraging steel is a carbonless alloy of iron that contains molybdenum, nickel, titanium and cobalt. Its properties change with the configuration of elements and temperature used when producing the metal. Maraging steel is used in various industries, including the military, aerospace and manufacturing.
  
  

Tungsten Carbide

• Tungsten carbide is a bluish-gray, man-made metal compound, created by heating the element tungsten with carbon and cementing that mixture with other metals such as nickel and cobalt. In is used in a wide range of applications from jewelry to drilling equipment.