玉石及硬度基本概念（Basic concepts of jade and hardness）.docVIP

玉石及硬度基本概念（Basic concepts of jade and hardness） Basic concept of jade hardness Basic concept Hardness is divided into: scratch hardness. Mainly used to compare the degree of hardness and hardness of different minerals, the method is to choose a hard end of one end of the soft bar, the material will be measured along the bar, according to the location of scratches to determine the soft and hard material to be measured. Qualitatively, a hard object has a long scratch, and a soft object has a short scratch. Pressing hardness. Mainly used in metal materials, the method is to use a certain amount of load will press the pressure head into the measured material, to the surface of the plastic deformation of the size of the material to compare the soft and hard material. Because of the pressure head, load and duration of the load, there are many kinds of indentation hardness, such as Brinell hardness, Rockwell hardness, hardness and microhardness of Vivtorinox. The Scleroscope hardness. Mainly used for metal materials, the method is to make a small hammer made from a certain height free fall impact specimen material is measured, and the sample stored in the impact process (and release) how much strain energy (height measurement by small hammer rebound to determine the hardness of the material). In early 1822, Friedrich Mohs proposed the Mohs hardness tester. According to the extent they are divided into ten levels: 1) 2) 3) talc gypsum calcite fluorite 4) 5) 6) 7) apatite feldspar quartz Topaz 8) 9) 10) diamond corundum simple memory method: talc, quartz, fluorite and phosphorus long Huang Yugang diamond. The differences in hardness between different levels are not equal, and the relative size of hardness is indicated only between grades. The most common steel hardness test method is to use file on the edge file eraser, presented by the surface scratch depth to determine its hardness level. This method is called filing test, which is not very scientific. Hardness testing mach