Vitreous refers to a material in an
amorphous, glassy state (in contrast to a crystallinestate). In such a state, the constituent atoms do not exhibit the long-range orderthat is characteristic of crystals. However, they still exhibit short-range order -- the separation of atoms and/or the lengths of covalent bonds are very close to their typical equilibrium distances. The creation of a vitreous material by supercoolingor by addition of additives prior to cooling is called vitrification.
Under certain conditions, vitreous materials may begin to rearrange themselves into
crystals. This process is referred to as devitrification. Natural volcanicglass, obsidian, will de-vitrify or crystallize over extended periods of geologic time. Devitrification can also occur in glass items that are regularly washed in dishwashers due to the chemicals involved in their detergents. [ [http://www.newi.ac.uk/buckleyc/materials.htm#Glass Ancient glass] (has a section mentioning devitrification)]
*When applied to whiteware
ceramics, vitreous means the material has an extremely low permeability to liquids, often but not always water, when determined by a specified test regime. The microstructure of whiteware ceramics frequently contain both amorphousand crystalline phases.
*A vitreous luster in
mineralogyrefers to a glassy luster or sheen of a mineral surface. The minerals quartzand fluoriteexhibit a vitreous luster.
vitreous humour(British spelling) or vitreous humor (U.S. spelling) is the clear gel that fills the space between the lens and the retina of the eyeball of humans and other vertebrates.
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