|WikiProject Glass||(Rated C-class, Top-importance)|
|WikiProject Chemical and Bio Engineering|
I don't understand the difference between this and glass. Aren't both non-crystalline silicon dioxide? - Omegatron 17:57, Jun 13, 2005 (UTC)
- Glass is about 70% silica, Fused quartz is much more pure. See the section on Glass Ingredients. -dmmaus 03:09, 13 December 2005 (UTC)
- To be clear, fused quartz is a type of glass. It's just glass with higher silica content than normal (ideally 100%).--Srleffler 15:31, 19 April 2006 (UTC)
This page would be better renamed to fused silica (and the text adjusted accordingly). "Fused quartz" is a misnomer, and leads to confusion. Quartz is a crystal. Fused silica is a glass. Both are forms of the chemical compound silica. The term "fused quartz" is unnecessarily confusing.--Srleffler 15:31, 19 April 2006 (UTC)
Synthetic fused silica is made from a silica-rich chemical (normally) using a Chemical Vapour Deposition (CVD) process. (In the optical industry this material is usually simply called "Fused silica" and this has the highest purity - typically >99.9999% silicon dioxide)
Fused quartz is made by fusing quartz crystal. (Typically >99.9% silicon dioxide)
Fused silica is made by fusing silica sand. (This has the lowest purity - typically 99.8% silicon dioxide.)
All these terms are valid and simply referring to them all as "fused silica" would be incorrect.
--George Reywer 12:37, 21 April 2006 (UTC)
I first heard the term "fused quartz" on television the other day, referred to as a special glass that can withstand more heat than normal glass. I wanted to know more about it and ended up here. I was quite disappointed to discover that this page talks a whole lot about "fused silica" and very little about "fused quartz" - at least as far as I can tell as a total newbie to the subject. It seems to me that most of the content should be moved to a page on fused silica, and the one paragraph about fused quartz expanded to talk about its unique properties. I can't do this, because I don't know anything about it. These are just my thoughts. Subversified (talk) 16:51, 29 February 2008 (UTC)
In light of recent simulations  it appears neutron stars may not be as smooth as previously thought. Perhaps the neutron star comment in the caption should be removed. 220.127.116.11 (talk) 17:58, 1 June 2009 (UTC)
Comment about optical properties:
The Sellmeier equation coefficients taken from Malitson (1965 - Interspecimen Comparison of the Refractive Index of Fused Silica) are measured and intended for 20°C. These values where determined at 20°C and 30°C only and in section "V. Thermal coefficients of index" it is clarified that a simple relation for various temperatures over this massive wavelength range for a precise calculation of the refractive index is not valid.
As a reference for the temperature dependence refractive index the following paper can be used: "The temperature dependence of the refractive indices of fused silica and crystal quartz T Toyoda and M Yabe 1983 J. Phys. D: Appl. Phys. 16 L97 doi: 10.1088/0022-3727/16/5/002)"
However, it was only possible to cover a range from 0.45 to 1.6 micron and 20°C to 400°C.
The statements about quartzite are problematic. The high temperatures required for fusion of quartz do no occur in the crust of the Earth except when meteoritic impacts are involved. Most quartzites are the result of slow solution/precipitation events in aqua, not fusion. Captainbeefart (talk) 15:37, 28 May 2011 (UTC)
That's not fused quartz, it's a cheap polymer resin (used on later EPROMs). The ones with a glass window have this added externally to the case, as a coverslip. Andy Dingley (talk) 10:56, 14 May 2013 (UTC)