Scratch hardness Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was developed by mineralogist Friedrich Mohs in 1820 (see Mohs scale). It is based on relative scratch hardness, with talc assigned a value of 1 and diamond assigned a value of 10. Mohs' scale had two limitations; it was not linear, and most modern abrasives fall between 9 and 10. Raymond R. Ridgway, a research engineer at the Norton Company, modified the Mohs scale by giving garnet a hardness of 10 and diamond a hardness of 15. Charles E.
Marble Rocks one side to another. This gave the Gorge its local name- Bandar Kudni (meaning- Monkey's jumping place). The white marbles are predominantly rich in magnesium and are closer in hardness to soap stone. This softness allows them to be carved. The area also contains blue and brown colored marble. The area has many tourist activities. There is a cable car to take visitors across the gorge, row boats for guided tours of the river downstream of the falls, and many small shops filled with crafts made from the local materials. Marble Rocks The Marble Rocks is an area along the