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MineralsZircon

14th Feb 2011 10:49 UTCClosed Account 🌟

I have noticed that there is a little confusion on the refractive indices of zircon on the web. Mindat lists: nω = 1.925 - 1.961 nε = 1.980 - 2.015 but other sites state nω and nε in reverse order (e.g.: http://webmineral.com/data/Zircon.shtml ). Could somebody knowledgable comment on this?

Branko

14th Feb 2011 16:21 UTCRonald John Gyllenhammer Expert

Hi Branko,

Mindat data is correct. Since Zircon is tetragonal, it is uniaxial, that is with a single optic axis. Also, since ε is greater than ω the optic sign is (+). This should be true in all cases. Only when when Zircon is metamict can it show some biaxial characteristics but minor only and e' (ε-ω) should still always be positive never negative. Mindat uses the same optical data for Zircon as is listed for Zircon in Handbook of Mineralogy.

Ron

14th Feb 2011 16:33 UTCClosed Account 🌟

Ron,

thanks! If the indices of refraction were as stated on webmineral.com, zircon would be optically negative, which is in fact what they claim. So that alone is no clear indication on who is right and who is wrong. But I tend to believe Mindat, because it is almost always correct. The Handbook of Mineralogy is another indication on that.

Branko

14th Feb 2011 17:03 UTCUwe Kolitsch Manager

Ron is completely right.

27th Sep 2013 00:35 UTCmastram hathesh

i want thermodynamic datas of zircon.

27th Sep 2013 03:47 UTCRonald John Gyllenhammer Expert

Hi Mastram,

If you are looking for thermodynamic properties of Zircon, try this link and go to page 28 of the paper or page 34 of the pdf under "Ortho and Ring Structure Silicates." Additionally, temp. dependent data sets for Zircon on pages 371-372 of the paper or pages 377-378 of the pdf. Good luck to you.

http://pubs.usgs.gov/bul/1452/report.pdf

Ron