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chromite

(Encyclopedia)chromite krōˈmīt [key], dark brown to black mineral. It is an iron-chromium oxide, FeCr2O4, with traces of magnesium and aluminum. Its crystals are octahedral, but rare; it usually occurs as irregu...

amphibole

(Encyclopedia)amphibole ămˈfəbōlˌ [key], any of a group of widely distributed rock-forming minerals, magnesium-iron silicates, often with traces of calcium, aluminum, sodium, titanium, and other elements. The ...

garnet

(Encyclopedia)garnet, name applied to a group of isomorphic minerals crystallizing in the cubic system. They are used chiefly as gems and as abrasives (as in garnet paper). The garnets are double silicates; one of ...

silicate

(Encyclopedia)silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may b...

Davy, Sir Humphry

(Encyclopedia)Davy, Sir Humphry, 1778–1829, English chemist and physicist. The son of a woodcarver, he received his early education at Truro and was apprenticed (1795) to a surgeon-apothecary at Penzance. While d...

chelating agents

(Encyclopedia)chelating agents kēˈlātĭng [key]. Certain organic compounds are capable of forming coordinate bonds (see chemical bond) with metals through two or more atoms of the organic compound; such organic ...

Aurora, cities, United States

(Encyclopedia)Aurora ərôrˈə, ô– [key]. 1 City (2020 pop. 386,261), Adams and Arapahoe counties, N central Colo., a growing suburb on the east side of Denver; inc. 1903. Founded d...

bromide

(Encyclopedia)bromide, any of a group of compounds that contain bromine and a more electropositive element or radical. Bromides are formed by the reaction of bromine or a bromide with another substance; they are wi...

alkaline-earth metals

(Encyclopedia)alkaline-earth metals, metals constituting Group 2 of the periodic table. Generally, they are softer than most other metals, react readily with water (especially when heated), and are powerful reducin...

Midland, cities, United States

(Encyclopedia)Midland. 1 City (1990 pop. 38,053), seat of Midland co., central Mich., in the Saginaw valley at the confluence of the Tittabawassee and Chippewa rivers; inc. 1887. Midland owes its development after ...