Mohs scale of mineral hardness integrity, they are not considered "scratches" for the determination of a Mohs scale number. The Mohs scale is a purely ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. The table below shows the comparison with the absolute hardness measured by a sclerometer, with pictorial examples. On the Mohs scale, a streak plate (unglazed porcelain) has a hardness of approximately 7.0. Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. The table below
Measuring the Mind causal factor within a subject. This chapter discusses measurement scales as the central concept of representational measurement theory. The chapter looks at the history behind psychological measurement scales and also at attempts to formalise measurement properties such as additive conjoint measurement. Borsboom also discusses what he terms “the problem of error”, that is the inability of such theories to handle the error that is intrinsic within psychological measurement. Measuring the Mind Measuring the Mind: Conceptual Issues in Contemporary Psychometrics is a book by Dutch academic Denny Borsboom, Assistant Professor of Psychological Methods at the University of Amsterdam, at time of