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Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide ). The atoms are linked in a continuous framework of SiO 4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO 2. Quartz is, therefore, classified structurally as a framework silicate mineral and ...
List of refractive indices. Refraction at interface. Many materials have a well-characterized refractive index, but these indices often depend strongly upon the frequency of light, causing optical dispersion. Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers .
Limestone. Limestone ( calcium carbonate CaCO3) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of CaCO3. Limestone forms when these minerals precipitate out of water containing dissolved calcium.
Tuff can be classified as either igneousor sedimentary rock. It is usually studied in the context of igneous petrology, although it is sometimes described using sedimentologicalterms. Tuff is often erroneously called tufa in guidebooks and in television programs but tufais a form of travertine. Volcanic ash.
Assassin's Creed: Altaïr's Chronicles is a spin-off for the Nintendo DS, Windows Phone, Android, iOS, webOS, Symbian, and Java ME, originally released in February 2008. The game is a prequel to the first Assassin's Creed , taking place in the year 1190, and follows Altaïr as he attempts to retrieve an artifact called the Chalice from the ...
The hypothesis of dark matter has an elaborate history. [18] [19] In the appendices of the book Baltimore lectures on molecular dynamics and the wave theory of light where the main text was based on a series of lectures given in 1884, [18] Lord Kelvin discussed the potential number of stars around the Sun from the observed velocity dispersion of the stars near the Sun, assuming that the Sun ...
Judas Priest are an English heavy metal band formed in Birmingham in 1969. They have sold over 50 million albums [ 2 ] and are frequently ranked as one of the greatest metal bands of all time. Judas Priest have also been referred to as one of the pioneers of the new wave of British heavy metal (NWOBHM) movement, [ 3 ][ 4 ] and are cited as a ...