Talk:Fluorite

message: The photograph of "Fluorite crystals" image:Fluorite_crystals_270x444.jpg actually shows cleaved fluorite octahedra.
Dlloyd 21:36, 17 Aug 2004 (UTC)
thread_title:  Fluorite image 

message: I got to this page from a redirect via Blue John and whilst Blue John is Fluorite not all fluorite is Blue John. Given that Blue John can only be found in Castleton,Derbyshire - surely a distinction should be made? CustardJack 09:56, 21 Apr 2005 (UTC)
replies: text: See Derbyshire Blue John. Dave.Dunford (talk) 20:23, 15 March 2012 (UTC)
thread_title:  Blue john redirect 

message: My understanding of the reason for using fluorite in visible light optics is that it is:
1) cubic and therfore optically isotropic (only single refractive index)
2) it offered a third refractive index/dispersion combination, so that when combined in an "Apochromatic Triplet" with the conventional "flint" and "crown" type optical glasses, it allowed Red, Green and Blue light to be brought into focus on the same plane("apo-chromatic correction"), where using the conventional Achromatic double only two colours could be brought into focus on the same plane, the others focusing either infront or behind it.
I gather that the same correction effect can be achieved by leaving an air gap in a "doublet" so effectively creating an "air element".
3) it was available in clear, relatively colourless and relatively insoluble (in water)crystals.
The refractive index of fluorite is surprisingly low. In microscopic examination this causes fluorite grains in thin sections to stand out with high relief boundary contacts against the cementing medium used to mount the slide, and most other minerals, due to the fluorite having a significantly lower refractive index.
This low refractive index can be used to "look into" a scratched or worn specimen, as submerging it in water, especially salty or sugary water will surpress many of the surface reflections.
Apparently, the mineral cryolite has approximately the same refractive index as water, and gives the illusion of disappearing when submerged.
-- unsigned by 194.106.142.221 (talk) at 18:57_59, 27 June 2007
The article currently says:
"fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes."
While the low dispersion may be of interest in some special cases, like what above IP says about grains in microscopic slides, but I disagree that a *low* dispersion is what makes them valuable for telescopes and other optics. I believe it's just the fact that the dispersion is much *different* from that of glasses, so that in the combination of several different materials you get improved color correction, like what above IP says about the apochromatic triplet.
--BjKa (talk) 12:38, 14 February 2018 (UTC)
thread_title:  Optics of Fluorite 

message: Under the Blue John section it says "Recent deposits in China have produced fluorite with coloring and banding similar to the classic Blue John stone" Should that read "recently discovered deposits"? Richerman (talk) 16:31, 24 June 2009 (UTC)
replies: text: Yes I'm sure it should. I've made the change.  And because it is a separate location, I've also made it a separate paragraph. Feline Hymnic (talk) 18:51, 25 June 2009 (UTC)
thread_title:  Blue John 

message: At the end of the uses section the text says something like strong hexagonal crystal structure. Normally this mineral is considered to be brittle and the crystal structure is not hexagonal but cubic!  —Preceding unsigned comment added by 150.227.15.253 (talk) 12:52, 22 March 2010 (UTC)
thread_title:  Uses 

message: There should be a section on antifluorite structure if "antifluorite" redirects to this page. 69.181.153.214 (talk) 05:03, 22 January 2012 (UTC)
replies: text: Anti-fluorite really seems to have nothing to do with fluorite. It's just a type of crystal structure where the cations and anions are reversed from the CaF2 structure. Li2O, Na2O, K2O, UO2, ThO2 and Be2C are examples. I suppose it deserves its own page if someone out there knows more than me. Pelirojopajaro (talk) 14:22, 31 October 2019 (UTC)
replies: text: See Anti-structure, to which Antifluorite directs now.--Smokefoot (talk) 17:01, 31 October 2019 (UTC)
thread_title:  Antifluorite section? 

message: Substituted at 15:18, 29 April 2016 (UTC)
thread_title:  Assessment comment 

message: Hello fellow Wikipedians,
I have just modified one external link on Fluorite. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive https://web.archive.org/web/20140209105809/http://www.ukminingventures.com/WeardaleMines.htm to http://www.ukminingventures.com/WeardaleMines.htm
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
Cheers.—InternetArchiveBot (Report bug) 23:21, 2 October 2017 (UTC)
thread_title:  External links modified 

message: Fluorite as a raw material is used to produce one of the materials in solar photo-voltaic panels, although I know nothing of the details. Now well into 2024, is there enough world wide usage for this purpose to warrant a mention? 2001:8003:E40F:9601:5C39:E04:5AE1:26F9 (talk) 09:16, 7 April 2024 (UTC)
thread_title:  Another "use"?