Dolomite (pronounced /ˈdɒləmaɪt/) is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate CaMg(CO3)2 found in crystals.
Dolomite rock (also dolostone) is composed predominantly of the dolomite mineral. Limestone that is partially replaced by dolomite is referred to as dolomitic limestone, or in old U.S. geologic literature as magnesian limestone. Dolomite mineral was first described in 1791 as the rock by the French naturalist and geologist, Déodat Gratet de Dolomieu (17501801) for exposures in the Dolomite Alps of northern Italy.
Dolomite mineral is used as an ornamental stone, a concrete aggregate and as a source of magnesium oxide. It is an important petroleum reservoir rock, and serves as the host rock for large strata-bound Mississippi Valley-Type (MVT) ore deposits of base metals (that is, readily oxidized metals) such as lead, zinc, and copper. Where calcite limestone is uncommon or too costly, dolomite is sometime used in its place as a flux (impurity remover) for the smelting of iron and steel. Large quantities of processed dolomite are used in the production of float glass (flat glass)
In horticulture, dolomite and dolomitic limestone are added to soils and soilless potting mixes to lower their acidity ("sweeten" them). Home and container gardening are common examples of this use.
How many different ways can SiO2 be organized into a neutral structure? That is what the Quartz Group is all about. It might amaze some to known that there is no less than nine different ways of organizing SiO2, referred to as silicon dioxide or silica. An alternate name for the Quartz Mineral Group is the Silica Group. Silicon and oxygen are the two most common elements in the Earth's crust, so perhaps their diverse modes of organization are not so unexpected. But in reality it is simply a matter of the temperature and pressure, especially at the time of crystallization, that determines which form silicon dioxide will organize into. Those nine different forms of silicon dioxide are listed in the table below with a few of their different characteristics.