Gibbsite: Difference between revisions

Revision as of 14:23, 21 February 2025

Aluminium hydroxide mineral

Gibbsite is a mineral form of aluminium hydroxide, with the chemical formula Al(OH)₃. It is an important ore of aluminium and is one of the three main phases of the aluminium hydroxide minerals, the others being boehmite and diaspore.

Structure

Gibbsite has a layered structure, with sheets of octahedrally coordinated aluminium ions bonded to hydroxide ions. The layers are held together by hydrogen bonds, which gives gibbsite its characteristic platy habit. The structure is similar to that of the brucite mineral, Mg(OH)₂, but with aluminium replacing magnesium.

Occurrence

Gibbsite specimen from the United States

Gibbsite is commonly found in bauxite deposits, which are the primary source of aluminium. It forms in tropical and subtropical climates through the weathering of aluminium-rich rocks. Gibbsite can also occur as a secondary mineral in hydrothermal veins and as a precipitate in some sedimentary environments.

Properties

Gibbsite is typically white, but it can also be colorless, gray, or tinted by impurities. It has a vitreous to pearly luster and a perfect basal cleavage. The mineral is relatively soft, with a Mohs hardness of 2.5 to 3.5, and has a specific gravity of about 2.3 to 2.4.

Uses

Gibbsite is an important ore of aluminium, and it is processed to produce alumina (Al₂O₃) through the Bayer process. Alumina is then used to produce aluminium metal via the Hall–Héroult process. Gibbsite is also used in the production of various aluminium compounds and as a filler in plastics and other materials.

Gallery

Gibbsite crystals showing typical platy habit

Gibbsite crystals showing typical platy habit

Related pages

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-{{Short description|An article about the mineral Gibbsite}}
+{{short description|Aluminium hydroxide mineral}}
 {{Use dmy dates|date=October 2023}}
-==Gibbsite==
+'''Gibbsite''' is a mineral form of aluminium hydroxide, with the chemical formula Al(OH)₃. It is an important ore of aluminium and is one of the three main phases of the aluminium hydroxide minerals, the others being [[boehmite]] and [[diaspore]].
-[[File:Gibbsite.jpg|thumb|right|Gibbsite sample]]
-'''Gibbsite''' is a mineral form of aluminum hydroxide, with the chemical formula Al(OH)_. It is an important ore of aluminum and is one of the main components of [[bauxite]], the principal ore of aluminum. Gibbsite is named after the American mineralogist [[George Gibbs (mineralogist)|George Gibbs]].
+==Structure==
+[[File:Gibbsite-crystal-3D-balls.png|thumb|left|3D ball model of the gibbsite crystal structure]]
+Gibbsite has a layered structure, with sheets of octahedrally coordinated aluminium ions bonded to hydroxide ions. The layers are held together by hydrogen bonds, which gives gibbsite its characteristic platy habit. The structure is similar to that of the [[brucite]] mineral, Mg(OH)₂, but with aluminium replacing magnesium.
+==Occurrence==
+[[File:Gibbsite-fiu14a.jpg|thumb|right|Gibbsite specimen from the United States]]
+Gibbsite is commonly found in bauxite deposits, which are the primary source of aluminium. It forms in tropical and subtropical climates through the weathering of aluminium-rich rocks. Gibbsite can also occur as a secondary mineral in hydrothermal veins and as a precipitate in some sedimentary environments.
 ==Properties==
-Gibbsite is a white, gray, or colorless mineral that crystallizes in the monoclinic system. It typically forms as tabular crystals, but can also occur in massive, stalactitic, or earthy forms. The mineral has a pearly luster and a Mohs hardness of 2.5 to 3.5, making it relatively soft. Gibbsite has a specific gravity of approximately 2.3 to 2.4.
+Gibbsite is typically white, but it can also be colorless, gray, or tinted by impurities. It has a vitreous to pearly luster and a perfect basal cleavage. The mineral is relatively soft, with a Mohs hardness of 2.5 to 3.5, and has a specific gravity of about 2.3 to 2.4.
-==Formation and Occurrence==
-[[File:Gibbsite-structure.png|thumb|left|Structure of Gibbsite]]
-Gibbsite commonly forms in tropical and subtropical climates as a result of the weathering of [[aluminosilicate]] minerals. It is often found in lateritic soils and is a major component of bauxite deposits. Gibbsite can also form as a secondary mineral in hydrothermal environments.
 ==Uses==
-Gibbsite is primarily used as an ore of aluminum. The extraction of aluminum from gibbsite involves the [[Bayer process]], where the mineral is dissolved in sodium hydroxide to separate the aluminum hydroxide from impurities. The aluminum hydroxide is then calcined to produce [[alumina]], which is subsequently reduced to aluminum metal through the [[Hall–Héroult process]].
+Gibbsite is an important ore of aluminium, and it is processed to produce alumina (Al₂O₃) through the [[Bayer process]]. Alumina is then used to produce aluminium metal via the [[Hall–Héroult process]]. Gibbsite is also used in the production of various aluminium compounds and as a filler in plastics and other materials.
-==Related Minerals==
+==Gallery==
-Gibbsite is part of the [[aluminum hydroxide]] group, which includes other polymorphs such as [[boehmite]] and [[diaspore]]. These minerals are also important constituents of bauxite and are used in the production of aluminum.
+<gallery>
+File:Gibbsite-270400.jpg|Gibbsite crystals showing typical platy habit
+</gallery>
-==See also==
+==Related pages==
 * [[Bauxite]]
-* [[Aluminum]]
+* [[Aluminium oxide]]
-* [[Bayer process]]
+* [[Boehmite]]
-* [[Hall–Héroult process]]
+* [[Diaspore]]
-==Related pages==
-* [[Alumina]]
-* [[Laterite]]
-* [[Hydrothermal mineral deposit]]
 [[Category:Aluminium minerals]]
 [[Category:Hydroxide minerals]]
-[[Category:Monoclinic minerals]]
+[[Category:Trigonal minerals]]