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
Softer, Softest Hole's performance on "MTV Unplugged" on Valentine's Day 1995, Love introduced the song as "[being] about the girl that always smelled like pee in your class" and also claimed it was autobiographical and not about former MTV producer, Tabatha Soren. Despite being credited on record as a collective authorship by all members of Hole, according to Broadcast Music Incorporated's website, the authors of the song are only Eric Erlandson and Courtney Love. A promotional music video was never recorded for "Softer, Softest", however, the version of the song performed at "MTV Unplugged" in 1995 was used a music video though