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Which is the dominant feldspar in basalt?
The dominant feldspar in basalt is usually plagioclase feldspar, specifically the calcium-rich variety called labradorite. This feldspar is commonly found in basaltic rocks due to the high calcium content in the magma from which basalt is formed.
What is the first minerals to form when magma cools that are rich in iron calcium and magnesium?
The first minerals to form when magma cools and is rich in iron, calcium, and magnesium are typically olivine, pyroxene, and/or plagioclase feldspar. These minerals have high melting points and tend to crystallize early as the magma cools.
How feldspars differ from one another?
Feldspars are classified based on their chemical composition into three main groups: potassium feldspar, plagioclase feldspar, and sodium feldspar. Potassium feldspar includes orthoclase and microcline, while plagioclase feldspar includes albite, oligoclase, and labradorite. Sodium feldspar primarily consists of albite. Each type of feldspar has a unique mineral structure and varying ratios of sodium, potassium, and calcium ions.
An igneous rock that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals has a composition that is?
An igneous rock that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals is classified as a basaltic or mafic rock. This composition typically indicates a formation from a relatively high-temperature magma that is rich in iron and magnesium. The presence of plagioclase feldspar suggests a significant amount of sodium and calcium in the rock's mineral makeup. Overall, this rock type is commonly associated with volcanic activity and can be found in oceanic crust.
Why are olivine and calcium-rich plagioclase often found together in igneous rocks?
Because both crystallize at similar temperatures and pressures according to Bowen's Reaction Series.
Which is the dominant feldspar in basalt?
The dominant feldspar in basalt is usually plagioclase feldspar, specifically the calcium-rich variety called labradorite. This feldspar is commonly found in basaltic rocks due to the high calcium content in the magma from which basalt is formed.
What is the most calcium-rich variety of plagioclase feldspar called?
The most calcium-rich variety of plagioclase feldspar is called anorthite. It contains a high proportion of calcium compared to sodium and aluminum, giving it its characteristic composition and properties.
What is a sodium an calcium feldspar with twinning striations called?
A sodium feldspar with twinning striations is called albite, while a calcium feldspar with twinning striations is called anorthite.
What is the first minerals to form when magma cools that are rich in iron calcium and magnesium?
The first minerals to form when magma cools and is rich in iron, calcium, and magnesium are typically olivine, pyroxene, and/or plagioclase feldspar. These minerals have high melting points and tend to crystallize early as the magma cools.
What is the most common element found in orthoclase feldspar but not in plagioclase feldspar?
The most common element found in orthoclase feldspar but not in plagioclase feldspar is potassium (K). Orthoclase is a potassium-rich feldspar, typically represented by the chemical formula KAlSi3O8. In contrast, plagioclase feldspar is a solid-solution series that primarily consists of sodium (Na) and calcium (Ca) in its composition, lacking potassium.
What mineral will form phenocrystals in a basalt?
Most commonly one expects the calcium-feldspar plagioclase as phenocryst.
What is the mineral composition of syenite?
Syenite is primarily composed of alkali feldspar minerals such as orthoclase and plagioclase feldspar, along with small amounts of other minerals such as quartz, hornblende, and mica. It lacks significant amounts of calcium-rich plagioclase feldspar, which distinguishes it from granite.
What type of feldspar contain either sodium or calcium?
Both sodium and calcium can occur with a variety of other metallic elements or silicon. Perhaps you would like to review the wikipedia article about feldspar.
What are two feldspars found in granite?
Granite contains plagioclase feldspar and potassium feldspar. It really depends on the composition of the magma from which it forms. If the granite has a lot of pink in it, chances are it is potassium feldspar (K-Spar). If it is dominated by white, then the feldspar is probably plag.
What are the types of feldspar?
There are broadly three main types of feldspars: calcium, sodium and potassium. They have the following general chemical formulas:KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8The endmember mineral states are known as K-Feldspar, Albite and Anorthite which are the potassium, sodium and calcium feldspars respectively.There can be a mix of calcium and sodium (more correctly termed solid solutions) in Feldspars between Albite and Anorthite which are known generally as Plagioclase feldspars.For more information please see the related question
How feldspars differ from one another?
Feldspars are classified based on their chemical composition into three main groups: potassium feldspar, plagioclase feldspar, and sodium feldspar. Potassium feldspar includes orthoclase and microcline, while plagioclase feldspar includes albite, oligoclase, and labradorite. Sodium feldspar primarily consists of albite. Each type of feldspar has a unique mineral structure and varying ratios of sodium, potassium, and calcium ions.
An igneous rock that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals has a composition that is?
An igneous rock that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals is classified as a basaltic or mafic rock. This composition typically indicates a formation from a relatively high-temperature magma that is rich in iron and magnesium. The presence of plagioclase feldspar suggests a significant amount of sodium and calcium in the rock's mineral makeup. Overall, this rock type is commonly associated with volcanic activity and can be found in oceanic crust.
