What minerals are in amphibolite?
What minerals are in amphibolite?
The mineral composition of the amphibolites is simple and mostly contains hornblende and plagioclase, with variable amounts of anthophyllite, garnet, mica, quartz, and epidote. The rocks may originate from pelitic sediments, with amphibole (hornblende), plagioclase, and typically include green pyroxene.
Is amphibole a mineral or rock?
metamorphic rock
Amphibolite is a dark, heavy, metamorphic rock composed mostly of the mineral amphibole. Amphibolites have very little to no quartz. “Amphibole” refers not to a single mineral, but to a group of minerals.
What is the variety of amphibole mineral group?
Introduction
| Mineral group | Asbestos variety | Nominal chemical formulaea |
|---|---|---|
| Amphibolec | Amosite | (Fe2+Mg)7Si8O22(OH)2 |
| Amphibole | Crocidolite | Na2Fe3+(Fe2+Mg)3Si8O22(OH)2 |
| Amphibole | Anthophyllite | Mg7Si8O22(OH)2 |
| Amphibole | Actinolite | Ca2Fe42+MgSi8O22(OH)2 |
What is the color of amphibolite?
Amphibolite is a grouping of rocks composed mainly of amphibole and plagioclase, with little or no quartz. 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.
What minerals are in the Protolith?
Pelitic protoliths are mainly composed of clay minerals derived from weathered and eroded continental crust. With increasing metamorphic grade, they are transformed to slates, phyllites, mica-schists, and granulites.
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.
How amphibole is 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.