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Graphic texture is commonly created by exsolution and devitrification and immiscibility processes in Fen, Philip M., 1986, ''On the Origin of Graphic Granite,'' American Mineralogist, Vol. 71, pp. 325-330
/ref> Exsolved
Gallery of graphic granites
Igneous rocks {{Petrology-stub
Graphic texture is commonly created by exsolution and devitrification and immiscibility processes in igneous
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The magma can be derived from partial ...
rocks.
It is called 'graphic' because the exsolved or devitrified minerals form lines and shapes which are reminiscent of writing.
Graphic granite
Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, 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 coo ...
is a leucocratic granitic rock consisting of alkali feldspar with exsolved quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
typically forming a distinctive repetitive pattern sometimes resembling cuneiform writing
Cuneiform is a Logogram, logo-Syllabary, syllabic writing system that was used to write several languages of the Ancient Near East. The script was in active use from the early Bronze Age until the beginning of the Common Era. Cuneiform script ...
. Experiments have shown that graphic granite texture is derived from large single crystals of quartz and feldspar interleaving to create the cuneiform illusion./ref> Exsolved
magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula . It is one of the iron oxide, oxides of iron, and is ferrimagnetism, ferrimagnetic; it is attracted to a magnet and can be magnetization, magnetized to become a ...
has graphic texture, as do some exsolution textures of pyroxene
The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...
, pyrite
The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic luster and pale brass-yellow hue ...
feldspar
Feldspar ( ; sometimes spelled felspar) is 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 ''plagiocl ...
and rarely other minerals.
See also
*List of rock textures
This page is intended to be a list of rock (geology), rock texture (geology), textural and morphology (materials science), morphological terms.
A
* Cumulate rocks, Adcumulate
* agglomerate, Agglomeritic
* Lustre (mineralogy)#adamantine, Adaman ...
*
* Peperite
References
External links
Gallery of graphic granites
Igneous rocks {{Petrology-stub