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Coltan. A piece of columbite–tantalite, size 6.0 × 2.5 × 2.1 cm. Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium's original American name columbium), and ...
Columbite, also called niobite, niobite-tantalite and columbate, with a general chemical formula of (Fe II, Mn II) Nb 2 O 6, is a black mineral group that is an ore of niobium. It has a submetallic luster, a high density, and is a niobate of iron and manganese. Niobite has many applications in areospace, construction and the medical industry.
Hematite. Hematite (/ ˈhiːməˌtaɪt, ˈhɛmə -/), also spelled as haematite, is a common iron oxide compound with the formula, Fe 2 O 3 and is widely found in rocks and soils. [6] Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of Fe. 3.
Ilmenite is a titanium-iron oxide mineral with the idealized formula FeTiO. 3. It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium [5] and the main source of titanium dioxide, which is used in paints, printing inks, [6] fabrics, plastics, paper, sunscreen, food and cosmetics.
This mineral group includes native metals, semi-metals, and non-metals, and various alloys and solid solutions. The metals are held together by metallic bonding, which confers distinctive physical properties such as their shiny metallic lustre, ductility and malleability, and electrical conductivity.
In scientific usage, shungite refers to a mineraloid which contains >98% carbon, and is used as a modifier to the host-rock's name, i.e. "shungite-bearing dolostone". [10] In popular usage, shungite-bearing rocks are sometimes themselves referred to as shungite. Shungite is subdivided into bright, semi-bright, semi-dull and dull on the basis of ...
Cubic, faces may be striated, but also frequently octahedral and pyritohedral. Often inter-grown, massive, radiated, granular, globular, and stalactitic. The mineral pyrite (/ ˈpaɪraɪt / PY-ryte), [6] or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S 2 (iron (II) disulfide).
It is an igneous rock. [6] Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. It is commonly found within the margins of rhyolitic lava flows known as obsidian flows. These flows have a high content of silica, granting them a high viscosity.