Mohs scale of mineral hardness Mohs scale of mineral hardness The Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. Created in 1812 by German geologist and mineralogist Friedrich Mohs, it is one of several definitions of hardness in materials science, some of which are more quantitative. The method of comparing hardness by seeing which minerals can visibly scratch others is, however, of great antiquity, having been mentioned by Theophrastus in his treatise "On Stones", c. 300 BC, followed by Pliny the Elder in his "Naturalis Historia", c.
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