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Index of Refraction of Glass, Flint

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Serway, Raymond & Faughn, Jerry. College Physics Sixth Edition. Canada: Thompson, 2003. Table 22.1 Indices of Refraction for Various Substances, Measured with Light of Vacuum [Wavelength of 589nm]
Substance Index of Refraction
Glass, Flint 1.66
Laven, Philip. Refractive Index. Encyclopedia Britannica. June 2008. Some typical refractive indices for yellow light (wavelength equal to 589 nanometres [10-9 metre]) are the following: air, 1.0002; water, 1.333; crown glass, 1.517; dense flint glass, 1.655; and diamond, 2.417. 1.655
Reed, Rick. Refraction of Light. University of Missouri–Columbia, 1998.
Substance Index of Refraction
Glass, flint, dense 1.66
Glass, flint, heaviest 1.89
Glass, flint, heavy 1.65548
Glass, flint, lanthanum 1.80
Glass, flint, light 1.58038
Glass, flint, medium 1.62725
Alward, Joseph. Refraction of Light. University of the Pacific, June 2008. Ratio of Speed of Light in Vacuum to Speed in Various Substances
Substance c/v
Glass (flint) 1.66
Nave, Carl. Index of Refraction. Hyper Physics. Georgia State University, 2006. Index of Refraction
Material Index
Flint Glasses 1.57-1.75
Heavy Flint glass 1.65
Extra dense flint, EDF-3 1.7200

The index of refraction is the ratio of the speed of light in air to its speed through another media. Flint glass has a relatively high refractive index of roughly 1.66, although some flint glasses are known to have refractive indexes as low as 1.45 and as high as 2.00.

Most flint, the mineral, is found in the form of fine-grained, dark-gray lumps mixed with calk and limestone. Early man used it to make spear heads and to start fires by striking it against hard metals. The name "flint glass" was given to the glassware that was perfected in the late 1670s. It contained a powdered flint that was added to the glass compound during the making process. The flint made the glass both heavy and clearer. At a later date in American history, lead was added to the glass. Lead was found to give the glass more clarity, resonance and weight. Lead was then replaced by lime during the civil war when lead was in shorter supply.

There are many uses for flint glasses. Flint glass can be fashioned into rhinestones, which are used as diamond simulants. Other uses include crystal chandeliers, crystal silverware and achromatic lenses and prisms.

Sydney Warshaw -- 2008