common members of the feldspar group are the plagioclase (sodium-calcium) feldspars and the alkali (potassium-sodium) feldspars. Feldspars make up about 60%...

Potassium feldspar refers to a number of minerals in the feldspar group, and containing potassium: Orthoclase (endmember formula KAlSi3O8), an important...

(phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and...

is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical...

Alkali feldspar granite, some varieties of which are called 'red granite', is a felsic igneous rock and a type of granite rich in the mineral potassium...

Feldspar is a group of rock-forming minerals including Alkali feldspar Alkali feldspar granite Potassium feldspar Feldspar may also refer to Community...

USS Feldspar (IX-159), a Trefoil-class concrete barge designated an unclassified miscellaneous vessel, was the only ship of the United States Navy to be...

Orthoclase, or orthoclase feldspar (endmember formula KAlSi3O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient...

20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar, because they are the most resistant minerals to the weathering processes...

Moonstone is a sodium potassium aluminium silicate ((Na,K)AlSi3O8) of the feldspar group that displays a pearly and opalescent schiller. An alternative name...

type Andesite – Type of volcanic rock Alkali feldspar granite – Type of igneous rock rich in alkali feldspar Anorthosite – Mafic intrusive igneous rock...

Sunstone is a microcline or oligoclase feldspar, which when viewed from certain directions exhibits a spangled appearance. It has been found in Southern...

describing igneous rocks that are relatively rich in elements that form feldspar and quartz. It is contrasted with mafic rocks, which are relatively richer...

Oligoclase is a rock-forming mineral belonging to the plagioclase feldspars. In chemical composition and in its crystallographic and physical characters...

Feldspar is an album by saxophonist and composer Matana Roberts, electric guitarist Sam Shalabi, and double bassist Nicolas Caloia. Consisting of seven...

subsolvus or two feldspar granites crystallisation occurs at high water pressures resulting in the formation of two types of feldspar as opposed to hypersolvus...

igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in...

a single feldspar as opposed to subsolvus granites in which two distinct types of feldspar are present. The distinctive character of feldspar in hypersolvus...

minerals; a granite is defined by proportions of quartz, alkali feldspar, and plagioclase feldspar. The other minerals in the rock are termed accessory minerals...

sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite. However, rarer...

crystals of feldspar. These feldspars are known as ternary because they contain significant components of all three endmember feldspars. The feldspar has partly...

intergrowths are associated with and commonly in contact with potassium feldspar. Myrmekite is formed under metasomatic conditions, usually in conjunction...

type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose...

Britain and Poland. The mine is likely the first feldspar mine in Sweden, starting in 1790. Feldspar mining was likely sporadic and based on manufacture...

a metamorphic rock that is altered granite composed of pink orthoclase feldspar, green epidote, and generally colorless quartz. It was first found in the...

rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various...

holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance...

alkali metal oxides. Monzonite is composed mostly of plagioclase and alkali feldspar. Syenodiorite is an obsolescent term for monzonite or for monzodiorite...

syenite is trachyte. The feldspar component of syenite is predominantly alkaline in character (usually orthoclase). Plagioclase feldspars may be present in small...

total content of quartz, alkali feldspar, and plagioclase (QAPF) and alkali feldspar makes up 35% to 90% of its total feldspar content. Feldspathoids are not...