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.
Lilyvale, The Rocks decades of the 20th century. The buildings on the site combine to form an interesting group, reminiscent of the lively and diverse early streetscapes and urban scale of The Rocks. "Lilyvale" was listed on the New South Wales State Heritage Register on 10 May 2002 having satisfied the following criteria. The place is important in demonstrating the course, or pattern, of cultural or natural history in New South Wales. "Lilyvale" (176 Cumberland Street) is an integral component of a group of 19th century houses in this section of Cumberland Street, which collectively illustrate the range, diversity and urban scale of