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
Mineral industry of Azerbaijan produced steel products from steel scrap. In 2005, production increased for practically all mineral commodities. Crude petroleum production increased by more than 43% compared with that of 2004. The country was developing its steel industry, although it is still on a small scale. Fuels accounted for 76% of the value of exports in 2005. The country’s major export was crude petroleum, almost all of which was sold on world markets rather than supplied to other CIS countries. Other mineral exports included petroleum refinery products and alumina. The country imported a variety of mineral commodities, including natural gas. Azerbaijan’s major mineral