Glass compositions

Source: Wikipedia. Pages: 45. Chapters: Egyptian faience, Lead glass, Tin-glazing, Vitreous enamel, Sodium silicate, Glass-to-metal seal, Bioglass, Salt glaze pottery, Borosilicate glass, Fused quartz, Phosphorus pentoxide, Uranium glass, Ground granulated blast furnace slag, Germanium dioxide, Soda-lime glass, Ceramic glaze, Boron trioxide, Low dispersion glass, Bioactive glass, Photochromic lens, Dichroic glass, Phosphate glass, Wood's glass, Sodium hexametaphosphate, Potassium silicate, Crown glass, Cranberry glass, Milk glass, Reagent bottle, Glass-ceramic-to-metal seals, Amorphous carbonia, Opaline glass, Flint glass, Scotchlite, Fluorophosphate glass, Cobalt glass, Glass with embedded metal and sulfides, Underglaze, Aluminosilicate, Borophosphosilicate glass, Vitrite, Ultra low expansion glass, Fluorosilicate glass, Leaded glass, Tellurite glass, Soluble glass. Excerpt: Egyptian faience is a non-clay based ceramic displaying surface vitrification which creates a bright lustre of various blue-green colours. Having not been made from clay it is often not classed as pottery. It is called "Egyptian faience" to distinguish it from faience, the tin glazed pottery associated with Faenza in northern Italy. Egyptian faience, both locally produced and exported from Egypt, occurs widely in the ancient world, and is well known from Mesopotamia, the Mediterranean and in northern Europe as far away as Scotland. From the inception of faience in the archaeological record of Ancient Egypt, the elected colors of the glazes varied within an array of blue-green hues. Glazed in these colours, faience was perceived as substitute for blue-green materials such as turquoise, found in the Sinai peninsula, and lapis lazuli, from Afghanistan. As early as the Predynastic graves at Naqada, Badar,el-Amrah, Matmar, Harageh, Avadiyedh and El-Gerzeh, glazed steatite and faience beads are found associated with these semi-precious stones. The association of faience with turquoise and lapis lazuli becomes even more conspicuous in Quennou's funerary papyrus, giving his title as the director of overseer of faience-making, using the word which strictly means lapis lazuli, which by the New Kingdom had also come to refer to the 'substitute', faience. The symbolism embedded in blue glazing could recall both the Nile, the waters of heaven and the home of the gods, whereas green could possibly evoke images of regeneration, rebirth and vegetation. The discovery of faience glazing has tentatively been associated with the copper industry: bronze scale and corrosion products of leaded copper objects are found in the manufacture of faience pigments. However, although the likelihood of glazed quartz pebbles developing accidentally in traces in copper smelting furnaces from the copper and wood ash is high, the regions in which these processes originate do not coincide. Although it a