flint glass


flint glass
an optical glass of high dispersion and a relatively high index of refraction, composed of alkalis, lead oxide, and silica, with or without other bases, sometimes used as the diverging lens component of an achromatic lens.
[1665-75]

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glass
also called  Crystal, or Lead Crystal,  

      heavy and durable glass characterized by its brilliance, clarity, and highly refractive quality. Developed by George Ravenscroft (Ravenscroft, George) (q.v.) in 1675, it ushered in a new style in glassmaking and eventually made England the leading glass producer of the world. Ravenscroft's experimentation was supported by the Worshipful Company of Glass Sellers, a body of English retailers long dissatisfied with the quality of glass from Isola (island) di Murano, Venice.

      The first clear crystal Ravenscroft produced, called flint glass because calcined flint was used as a base, decayed after a period of time. This fault was overcome by adding lead oxide to produce lead crystal. (“Flint glass” thus became a synonymous term for lead crystal, though flint is no longer part of its composition.) The Glass Sellers furnished the designs and set exacting standards for the product. Their earliest examples bear the seal of a raven's head. In time, the adaptation of European traditional styling to the new glass produced a genuine native English style of glassware.

      In the optical glass industry, flint glass is any highly refractive lead-containing glass used to make lenses (lens) and prisms (prism). Because it absorbs most ultraviolet light but comparatively little visible light, it is also used for telescope lenses. The light-dispersive power of flint glass can be made twice as high as that of crown glass (of conventional soda-lime composition), and the two complementary types of glass are cemented together to make lenses corrected for chromatic aberration. In the container glass industry, flint glass is any clear glass free of colouring.

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Universalium. 2010.

Look at other dictionaries:

  • flint-glass — [ flintglas ] n. m. inv. ou flint [ flint ] n. m. • 1764, 1855; angl. flint « silex » et glass « verre » ♦ Opt. Verre à base de plomb, très dispersif, utilisé en optique. ● flint ou flint glass nom masculin ( …   Encyclopédie Universelle

  • Flint glass — is optical glass that has relatively high refractive index and low Abbe number. Flint glasses are arbitrarily defined as having an Abbe number of 50 to 55 or less. The currently known flint glasses have refractive indices ranging between 1.45 and …   Wikipedia

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  • Flint glass — Glass Glass (gl[.a]s), n. [OE. glas, gles, AS. gl[ae]s; akin to D., G., Dan., & Sw. glas, Icel. glas, gler, Dan. glar; cf. AS. gl[ae]r amber, L. glaesum. Cf. {Glare}, n., {Glaze}, v. t.] [1913 Webster] 1. A hard, brittle, translucent, and… …   The Collaborative International Dictionary of English

  • flint-glass — flint ou flint glass (flint ou flint glas ) s. m. Verre en cristal servant avec le crown glass à faire les lentilles achromatiques des microscopes ; il est constitué par 3 atomes de quadrisilicate de plomb et 2 atomes de quadrisilicate de potasse …   Dictionnaire de la Langue Française d'Émile Littré

  • Flint glass — (Chem.) A soft, heavy, brilliant glass, consisting essentially of a silicate of lead and potassium. It is used for tableware, and for optical instruments, as prisms, its density giving a high degree of dispersive power; so called, because… …   The Collaborative International Dictionary of English

  • Flint glass — Flint Flint, n. [AS. flint, akin to Sw. flinta, Dan. flint; cf. OHG. flins flint, G. flinte gun (cf. E. flintlock), perh. akin to Gr. ? brick. Cf. {Plinth}.] 1. (Min.) A massive, somewhat impure variety of quartz, in color usually of a gray to… …   The Collaborative International Dictionary of English

  • flint glass — flint′ glass n. opt an optical glass of high dispersion and a relatively high index of refraction, composed of alkalis, lead oxide, and silica …   From formal English to slang

  • flint glass — n. a hard, bright glass containing lead oxide and having a high index of refraction, used for lenses, crystal, etc …   English World dictionary

  • flint glass — noun optical glass of high dispersion and high refractive index • Syn: ↑optical flint • Hypernyms: ↑optical glass * * * noun 1. : glass formerly made using calcined flints as a source of silica 2. : heavy brilliant glass that contains lead oxide …   Useful english dictionary


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