Quartzolite or silexite is an intrusive

igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma o ...

, in which the

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical f ...

is more than 90% of the rock's

felsic In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted with mafic rocks, wh ...

mineral content, with

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) felds ...

at up to 10%. Typically, quartz forms more than 60% of the rock, the rest being mostly feldspar although minor amounts of

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

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

may also be present. Quartzolite occurs as dykes,

sill Sill may refer to: * Sill (dock), a weir at the low water mark retaining water within a dock * Sill (geology), a subhorizontal sheet intrusion of molten or solidified magma * Sill (geostatistics) * Sill (river), a river in Austria * Sill plate, ...

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated ...

boss Boss may refer to: Occupations * Supervisor, often referred to as boss * Air boss, more formally, air officer, the person in charge of aircraft operations on an aircraft carrier * Crime boss, the head of a criminal organization * Fire boss, a ...

es and segregation masses; it is also found in association with greisen and

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silici ...

. Quartzolite is an extremely rare type of rock. No

extrusive rock Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. In ...

equivalent of quartzolite is known.

Synonyms

The use of the synonym "''silexite"'' is discouraged because it is the French word for

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...

, which is a

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

. Other less common synonyms are "''igneous quartz''" and "''peracidite''".

Examples

Chrastava Chrastava (; german: Kratzau) is a town in Liberec District in the Liberec Region of the Czech Republic. It has about 6,300 inhabitants. Administrative parts Chrastava is made up of town parts of Chrastava, Dolní Chrastava and Horní Chrastava, ...

, Czech Republic * Crag Mountain, Northfield, Massachusetts, United States * Jabal Hamra, Saudi Arabia * Keivy,

Kola Peninsula The Kola Peninsula (russian: Кольский полуостров, Kolsky poluostrov; sjd, Куэлнэгк нёа̄ррк) is a peninsula in the extreme northwest of Russia, and one of the largest peninsulas of Europe. Constituting the bulk ...

, Russia * Lyon Mountain quadrangle, New York state, United States * Moulting Pond, Newfoundland, Canada * Qiabukanzhuota, China * Saveh County, Iran * Smaaland Cove, South Georgia * South Mountains, Arizona, United States * Torrington, New South Wales, Australia

Formation

Some occurrences of quartzolite are unlikely to have an entirely igneous origin; for example, two types of quartzolite that are associated with deposits of topaz in and around the Mole

Granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies un ...

pluton In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

in Torrington, NSW, are believed to have formed in different ways. One type forms dykes and sills in the granite and in the surrounding

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

s. The other type has remnants of an earlier granite texture and is found on the outer edges of part of the pluton.

References

{{Reflist Intrusive rocks