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.
Scale for the Assessment of Negative Symptoms been developed to assess the positive and negative aspects of schizophrenia. The Scale for the Assessment of Negative Symptoms (SANS) is a rating scale to measure negative symptoms in schizophrenia. The scale was developed by Nancy Andreasen and was first published in 1984. SANS is split into 5 domains, and within each domain separate symptoms are rated from 0 (absent) to 5 (severe). The scale is closely linked to the Scale for the Assessment of Positive Symptoms (SAPS) which was published a few years later. These tools are made available for clinicians and for research purposes. Andreasen NC: Scale for