Minerals are most commonly classified by the Dana system. Minerals are identified according to hardness, specific gravity, color, luster, streak, cleavage and crystal form.Continue Reading
The Dana system of classification was devised by Professor James Dana of Yale University in 1848. His system classified minerals according to their chemical composition. For example, a halide has Cl (chlorine), Br (bromine), F (fluorine) or I (iodine) at the end of its chemical formula.
A new Dana system of classification contains 78 different classes of minerals based on composition and then further classified by type and group. To be considered a mineral, a substance must be an inorganic, naturally formed solid, with a specific chemical formula and a fixed internal structure. To test whether something is a mineral, there are several identification tests to which the substance is subjected, including its resistance to scratching, its density in comparison to water, its color, the degree of light it reflects, the color of the powdered mineral, its breakage pattern and its crystalline form.
There are over 4,900 different types of minerals known in the world.Learn more about Geology
Clay minerals are hydrous aluminium phyllosilicates that may contain varying amounts of iron, magnesium and alkali metals. These minerals are commonly found in the Earth's near-surface environments and form in soil and sedimentary deposits due to diagenetic and hydrothermal alteration of rocks.Full Answer >
Some examples of ferromagnesian minerals in mafic rock include olivine, pyroxene and amphibole. Rocks containing pyroxene and amphibole often also contain feldspar, a non-ferromagnesian mineral.Full Answer >
Placer mining is the extraction of minerals from alluvial deposits, often at the site of flowing water. Minerals that have been eroded from an upstream source and carried by a river, called placer, are deposited along the course of the water and buried in sediment to be later extracted with minimal effort.Full Answer >
More than 90 percent of the mineral composition of the Earth's crust is composed of silicate minerals. These silicate minerals differ with each specific compound, as each compound is composed of different elements to form the types of rock that constitute the Earth's crust.Full Answer >