Query: Granite is a solid.

Relevant passages:
Granite <=SEP=> Granite ( -LSB- pronˈɡrænᵻt -RSB- ) is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture . Granites can be predominantly white , pink , or gray in color , depending on their mineralogy . The word `` granite '' comes from the Latin granum , a grain , in reference to the coarse-grained structure of such a holocrystalline rock . Strictly speaking , granite is an igneous rock with between 20 % and 60 % quartz by volume , and at least 35 % of the total feldspar consisting of alkali feldspar , although commonly the term `` granite '' is used to refer to a wider range of coarse grained igneous rocks containing quartz and feldspar .   The term `` granitic '' means granite-like and is applied to granite and a group of intrusive igneous rocks with similar textures and slight variations in composition and origin . These rocks mainly consist of feldspar , quartz , mica , and amphibole minerals , which form an interlocking , somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole ( often hornblende ) peppering the lighter color minerals . Occasionally some individual crystals ( phenocrysts ) are larger than the groundmass , in which case the texture is known as porphyritic . A granitic rock with a porphyritic texture is known as a granite porphyry . Granitoid is a general , descriptive field term for lighter-colored , coarse-grained igneous rocks . Petrographic examination is required for identification of specific types of granitoids . The extrusive igneous rock equivalent of granite is rhyolite .   Granite is nearly always massive ( lacking any internal structures ) , hard and tough , and therefore it has gained widespread use throughout human history , and more recently as a construction stone . The average density of granite is between 2.65 and 2.75 g/cm3 ( 165.4 - 171.7 lb/ft3 ) , its compressive strength usually lies above 200 MPa , and its viscosity near STP is 3 -- 6 • 1019 Pa · s.   The melting temperature of dry granite at ambient pressure is ; it is strongly reduced in the presence of water , down to 650 ° C at a few kBar pressure .   Granite has poor primary permeability , but strong secondary permeability .

Igneous rock <=SEP=> 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 or lava . The magma can be derived from partial melts of existing rocks in either a planet 's mantle or crust . Typically , the melting is caused by one or more of three processes : an increase in temperature , a decrease in pressure , or a change in composition . Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks . Igneous rock may form with crystallization to form granular , crystalline rocks , or without crystallization to form natural glasses .

Crystallinity <=SEP=> Crystallinity refers to the degree of structural order in a solid . In a crystal , the atoms or molecules are arranged in a regular , periodic manner . The degree of crystallinity has a big influence on hardness , density , transparency and diffusion . In a gas , the relative positions of the atoms or molecules are completely random . Amorphous materials , such as liquids and glasses , represent an intermediate case , having order over short distances ( a few atomic or molecular spacings ) but not over longer distances .   Many materials , such as glass-ceramics and some polymers , can be prepared in such a way as to produce a mixture of crystalline and amorphous regions . In such cases , crystallinity is usually specified as a percentage of the volume of the material that is crystalline . Even within materials that are completely crystalline , however , the degree of structural perfection can vary . For instance , most metallic alloys are crystalline , but they usually comprise many independent crystalline regions ( grains or crystallites ) in various orientations separated by grain boundaries ; furthermore , they contain other crystallographic defects ( notably dislocations ) that reduce the degree of structural perfection . The most highly perfect crystals are silicon boules produced for semiconductor electronics ; these are large single crystals ( so they have no grain boundaries ) , are nearly free of dislocations , and have precisely controlled concentrations of defect atoms .   Crystallinity can be measured using x-ray crystallography , but calorimetric techniques are also commonly used .