Characteristics of amphibolite
How do you describe amphibole?
Amphibole (/ˈæmfəboʊl/) 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.
What is amphibolite texture?
The amphibolites are characterized by nematoblastic or granoblastic texture. Amphibolites are formed from more basic magmatites usually containing more magnesium amphibole (anthophyllite), and the ones crop up from weak basic and neutral magmatites containing nearly equal amounts of hornblende and Ca-plagioclase.
What is the significance of amphibole?
It is used as paving stones and as a veneer or facing on buildings (both for interior and exterior use). It is also used as crushed stone for the usual crushed stone applications such as road and railroad bed construction. In this application it is used locally, near the source of the amphibolite.
What is the color of amphibolite?
Amphibolite
| Type | Metamorphic Rock |
|---|---|
| Texture | Non-foliated to weakly-foliated; Medium-grained |
| Composition | Amphibole and Plagioclase |
| Index Minerals | Amphibole |
| Color | Black |
What is the classification of amphibolite?
Amphibolite is a coarse-grained metamorphic rock, predominantly composed of mineral amphibole and plagioclase feldspar. It can also contain minor amounts of other metamorphic minerals such as biotite, epidote, garnet, wollastonite, andalusite, staurolite, kyanite, and sillimanite.
What does amphibolite look like?
Amphibolite (/æmˈfɪbəlaɪt/) is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure.
What is the hardness of amphibolite?
between 5 and 6
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.
Where is amphibolite formed?
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.
What kind of mineral is amphibole?
hydrous minerals
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 texture in rocks?
Texture refers to the physical makeup of rock—namely, the size, shape, and arrangement (packing and orientation) of the discrete grains or particles of a sedimentary rock. Two main natural textural groupings exist for sedimentary rocks: clastic (or fragmental) and nonclastic (essentially crystalline).
What is the luster of amphibole?
Vitreous
Physical Properties for Hornblende
| Chemical Classification | Silicate |
|---|---|
| Luster | Vitreous |
| Diaphaneity | Translucent to nearly opaque |
| Cleavage | Two directions intersecting at 124 and 56 degrees |
| Mohs Hardness | 5 to 6 |
Is amphibolite foliated or Nonfoliated?
Amphibolite is a non foliated metamorphic rock that is mainly composed of mineral amphibole and plagioclase feldspar with little or no quartz.
What is the grain size of amphibolite?
0.1-1.2 mm
GRAIN SIZE: 0.1-1.2 mm. TEXTURE: Porphyroclastic.
What kind of mineral is amphibole?
hydrous minerals
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 kind of cleavage does amphibole exhibit?
Hornblende (an amphibole)
Instead of breaking in broad, single cleavage planes like the micas, the cleavage surface of an amphibole mineral tends to display a large number of small, offset planes that help give the mineral a splintery appearance.
What is amphibolite rock?
amphibolite, a rock composed largely or dominantly of minerals of the amphibole group. The term has been applied to rocks of either igneous or metamorphic origin. In igneous rocks, the term hornblendite is more common and restrictive; hornblende is the most common amphibole and is typical of such rocks.
Where is amphibolite found?
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.
What is the hardness of amphibole?
between 5 and 6
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.
Where is amphibole most commonly found?
It occurs as phenocrysts in several varieties of extrusive igneous rocks, such an andesite. It occurs as a detrital heavy mineral in sedimentary rocks. It forms in a number of gneissic rocks formed at moderate grades of metamorphism. Amphibolites are common metamorphic rocks consisting in large part of dark amphibole.
How do you identify a rocks 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.
Is amphibolite a sedimentary rock?
Amphibolite is a metamorphic rock, formed by regional metamorphosis either from sedimentary (para-amphibolites) or magmatic (ortho-amphibolites) protoliths.