What are Ore Minerals?
Ore minerals are minerals which contain metal elements in a sufficient concentration for economic extraction. Metallic ore minerals include native metal, sulfide and carbonate minerals, sulfosalts, and other ore minerals. Ore minerals are essential components of the lithosphere, which are the thin outer layers of the solid Earth – the crust and uppermost mantle.
The metal content of ore minerals can range from a few percent up to more than 99 percent. Ore minerals also plays a significant role in forming near-surface hydrothermal deposits, and are necessary components of mineralogical and geochemical exploration.
The composition of ore minerals is mostly determined by the composition of the host rock, or in other words, the mineral composition of ore minerals is strongly influenced by the composition of its surrounding environment. As a result, ore minerals can vary significantly in chemical composition, from element to element, from one ore deposit to another.
Native metal ore minerals are those which contain metal elements in their native form and occur as a single phase. Examples of native metal ore minerals include copper, silver, gold, titanium, tin, zinc, and lead. These metals are also referred to as first or special metals since they can be extracted from their ore minerals, often directly.
Sulfide ore minerals contain sulfur (S) in their chemical makeup, and are divided into two categories: primary and secondary. Primary sulfide ore minerals are formed when magma, which is molten rock, reacts with other elements to produce sulfide ore minerals. Some common examples of primary sulfide ore minerals include pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS), and galena (PbS).
Secondary sulfide ore minerals form when primary ore minerals are exposed to and altered by oxygen and water. Examples of secondary sulfide ore minerals include marcasite (FeS2), molybdenite (MoS2), cinnabar (HgS), and stibnite (Sb2S3).
Carbonate ore minerals generally contain carbon (C) and oxygen (O) and come in two forms: primary and secondary. Primary carbonate ore minerals are formed by the breakdown of preexisting rock material and the concentration of the carbonate ions. Examples of primary carbonate ore minerals are siderite (FeCO3), magnesite (MgCO3), and calcite (CaCO3).
Secondary carbonate ore minerals form when primary ore minerals are exposed to and altered by oxygen, water, and carbon dioxide. Some examples of secondary carbonate ore minerals include malachite (CuCO3), smithsonite (ZnCO3), and witherite (BaCO3).
Sulfosalts are minerals which contain sulfur (S) and oxygen (O), as well as one or more metals, such as lead (Pb), silver (Ag), bismuth (Bi), and arsenic (As). They are formed in hydrothermal deposits, commonly in hot springs.
Other ore minerals include those which contain phosphorus (P), silicon (Si), uranium (U), vanadium (V), and nickel (Ni). These ore minerals are referred to as “third level metals” and are found in deeper parts of the Earth.
In summary, ore minerals are minerals which contain metal elements in a concentration that is economically extractable. Ore minerals can vary greatly in composition and form, from native metal ore minerals to sulfides and carbonates, and are essential components of the lithosphere. They also play a significant role in hydrothermal deposits and mineral exploration.
