What is the mineral composition of amphibole?

Physical Properties for Hornblende

Chemical Classification	Silicate
Diagnostic Properties	Cleavage, color, elongate habit
Chemical Composition	(Ca,Na)2–3(Mg,Fe,Al)5(Al,Si)8O22(OH,F)2
Crystal System	Monoclinic
Uses	Very little industrial use

What is amphibole in chemistry?

Amphibole (/ˈæmfɪˌboʊl/) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain SiO. 4. tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.

Is amphibole a mineral or rock?

Amphiboles are a major group of hydrous minerals that occur in a wide range of rock types. They occur predominantly in metamorphic and igneous rocks of the Earth’s crust and upper mantle. Two metamorphic facies are defined by their characteristic amphiboles.

What is the crystal system of amphibole?

“Amphibole” refers not to a single mineral, but to a group of minerals. Most belong to the monoclinic crystal system, but some belong to the orthorhombic crystal system. They are silicate minerals containing SiO4 molecules. The SiO4 groups are connected to each other in double chains.

How do you identify amphibole in hand samples?

Long prismatic, acicular, or fibrous crystal habit, Mohs hardness between 5 and 6, and two directions of cleavage intersecting at approximately 56° and 124° generally suffice to identify amphiboles in hand specimens. The specific gravity values of amphiboles range from about 2.9 to 3.6.

What does amphibole look like?

It is typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure. The small flakes of black and white in the rock often give it a salt-and-pepper appearance. Amphibolite need not be derived from metamorphosed mafic rocks.

How is amphibole formed?

How Does Amphibolite Form? Amphibolite is a rock of convergent plate boundaries where heat and pressure cause regional metamorphism. It can be produced through the metamorphism of mafic igneous rocks such as basalt and gabbro, or from the metamorphism of clay-rich sedimentary rocks such as marl or graywacke.

How do you identify amphibole?

What does amphibole mean?

ambiguous
Amphiboles are found principally in metamorphic and igneous rocks. Amphibole, from the Greek amphibolos, meaning “ambiguous,” was named by the famous French crystallographer and mineralogist René-Just Haüy (1801) in allusion to the great variety of composition and appearance shown by this mineral group.

Where is amphibole most commonly found?

General considerations. Amphiboles are found principally in metamorphic and igneous rocks. They occur in many metamorphic rocks, especially those derived from mafic igneous rocks (those containing dark-coloured ferromagnesian minerals) and siliceous dolomites.

What is the color of amphibole?

Identification: Typically, amphiboles form as long prismatic crystals, radiating sprays and fibrous aggregates. They are generally dark coloured though their colours can range from colourless to white, green, brown, black, blue or lavender. This property is related to composition, particularly iron content.

What kind of minerals are found in amphibole crystals?

Amphibole ( /ˈæmfɪboʊl/) is an important group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain SiO. 4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.

Which is the chemical formula for the amphibole group?

The complex chemical composition of members of the amphibole group can be expressed by the general formula A 0–1B 2C 5T 😯 22(OH, F, Cl) 2, where A = Na, K; B = Na, Zn, Li, Ca, Mn, Fe 2+, Mg; C = Mg, Fe 2+, Mn, Al, Fe 3+, Ti, Zn, Cr; and T = Si, Al, Ti.

How are amphibole crystals different from pyroxenes?

Amphiboles can also be found as pseudomorphs after pyroxenes, often making the distinction even harder. Amphibole crystals can also be identified by their six-sided crystal cross sections. The amphibole group minerals are generally considered amongst the most complex silicate groups.

Where are the amphibole group minerals found in Canada?

Eudyalite (red) with arfvedsonite (black) from Kipawa River, Villedieu Township, Quebec, Canada. Size: 7 x 6 cm; photo: James St. John