Minerals

A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties.
The study of minerals is called mineralogy.

Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2. It is the birthstone of the month November. It crystallizes in the orthorhombic group and its crystals are mostly prismatic terminated by pyramidal and other faces, the basal pinacoid often being present. It has an easy and perfect basal cleavage, meaning that gemstones or other fine specimens have to be handled with care to avoid developing cleavage flaws. The fracture is conchoidal to uneven. Topaz has a hardness of 8, a specific gravity of 3.4–3.6, and a vitreous luster. Pure topaz is transparent but is usually tinted by impurities; typical topaz is wine or straw-yellow. They may be made white, gray, green, blue, pink or reddish-yellow and transparent or translucent.
The five features of minerals
*they are solids.
*they are formed naturally in the earth.
*they have the same chemical makeup throughout.
*they are not alive or made of living thing.
*they are definite arrangement of atoms.