Despite the abundance of silicons in the Earth's crust, not all minerals contain silicon. The atoms of many metals, which tend to lose electrons and become positively charged, like to bond with other atoms or groups of atoms that tend to gain atoms and become negatively charged. For example, atoms of sodium, a metal, and chlorine, a non-metal, pair up in equal numbers to form sodium chloride, also known as halite (or common table salt). Other important types of non-silicate minerals include carbonates, with metals bonded to groups of carbon and oxygen atoms; oxides, with metals joined to oxygen alone; sulfides, which consist of metal and sulfur atoms; and sulfates, in which groups of sulfur and oxygen atoms are joined with metal atoms.

Inside a mineral, atoms arrange themselves into a specific, repeating pattern called a crystal lattice or crystal structure. The smallest three-dimensional arrangement within the lattice is called a "unit cell," which is duplicated over and over again symmetrically. At the level of the everyday world, minerals that are growing without outside interference tend to form crystals that resemble their underlying crystal structures. Scientists call that kind of general, typical appearance a "crystal habit." Of course, conditions that existed during a mineral's formation or crystal growth may change its habit, but geologists still find this attribute to be a useful tool for identifying minerals. Scientists use more than three dozen adjectives to describe crystal habits. For example, natrolite and rutile can be acicular, or needlelike; quartz often forms hexagonal prisms; pyrite and halite typically crystallize as cubes; and mica is foliated or lamellar (layered).

Through ancient times and the Middle Ages smelting techniques did not change much and improvements were made by using different techniques to forge the steel. The disadvantage was that every object made of iron or steel had to be made one at a time by a blacksmith. Unlike copper and other metals, furnaces could not get hot enough to melt iron so that it could be cast into molds. About 300 years ago, Europeans developed a more efficient blast furnace that used coal instead of wood charcoal to produce cast iron. Being able to cast iron meant that iron and steel products could be mass-produced; this development eventually gave rise to the Industrial Revolution. Today's industries depend on steel, which is an alloy, or solid mixture, of iron with carbon, manganese, and other trace elements. This combination gives the metal additional strength and reduce iron's tendency to rust, or to bond with oxygen in the atmosphere. Another industrially important metal, aluminum, comes from the ore known as bauxite, a mixture of three aluminum oxide minerals. Until the 1880s, when humans learned how to separate the aluminum and oxygen atoms by running electricity through the aluminum oxide, metallic aluminum was extremely difficult to make, and thus more expensive than gold.