Mineralogy classified into density (often given as specific gravity); measures of mechanical cohesion (hardness, tenacity, cleavage, fracture, parting); macroscopic visual properties (luster, color, streak, luminescence, diaphaneity); magnetic and electric properties; radioactivity and solubility in hydrogen chloride (). "Hardness" is determined by comparison with other minerals. In the Mohs scale, a standard set of minerals are numbered in order of increasing hardness from 1 (talc) to 10 (diamond). A harder mineral will scratch a softer, so an unknown mineral can be placed in this scale by which minerals it scratches and which scratch it. A few minerals such as calcite and kyanite
Schiehallion including dog's mercury, lily of the valley and wood anemone. The majority of Schiehallion consists of Quartzite, a rock formed from an original sand by heat and pressure. Quartzite is a white or pinkish rock, in which the dominant mineral is Quartz. Quartz is hard, being number seven on the Mohs scale of mineral hardness. It is able to scratch glass since it is harder than glass. People often mistakenly think that Schiehallion is an extinct volcano because its shape is reminiscent of an active volcano. If fact it formed by sedimentary processes and the shape is the result of