# \#refractive-index

**URL:** https://scanalyst.fourmilab.ch/tag/refractive-index/4626.md

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## [Ulexite “Television Stone”—How Does It Work?](https://scanalyst.fourmilab.ch/t/ulexite-television-stone-how-does-it-work/4256)

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**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\
**Replies:** 1\
**Last updated:** [27 January 2024 21:56 UTC](https://scanalyst.fourmilab.ch/t/ulexite-television-stone-how-does-it-work/4256 "2024-01-27T21:56:20Z")

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Ulexite was first described in 1840 by German chemist Georg Ludwig Ulex after whom it is named. Its remarkable optical properties were not explained until 1957 when a paper, “Image Projection by Fibrous Min…

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## [The Most Reflective Mirror Is Made from Transparent Plastic](https://scanalyst.fourmilab.ch/t/the-most-reflective-mirror-is-made-from-transparent-plastic/3595)

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**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\
**Replies:** 14\
**Last updated:** [19 January 2024 02:36 UTC](https://scanalyst.fourmilab.ch/t/the-most-reflective-mirror-is-made-from-transparent-plastic/3595 "2024-01-19T02:36:12Z")

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Here is more about dielectric mirrors, which can provide up to 99.999% reflectivity for a narrow band of wavelengths or, for a broadband mirror, over 99.5% of visible light across all wavelengths. (Alumini…