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GeneralUser gallery only Iris quartz
29th Jun 2017 18:33 UTCJason Evans
29th Jun 2017 18:45 UTCAlfredo Petrov Manager
29th Jun 2017 18:58 UTCJason Evans
29th Jun 2017 20:37 UTCWayne Corwin
Good job !
29th Jun 2017 20:51 UTCAlfredo Petrov Manager
29th Jun 2017 21:18 UTCWayne Corwin
11th Jul 2017 05:25 UTCSteven Kuitems Expert
11th Jul 2017 19:39 UTCMatt Ciranni
I've seen a few crystals like this in rock shops, but I was told they were coated with a substance to give that iris iridescence.
11th Jul 2017 20:02 UTCAlfredo Petrov Manager
https://www.mindat.org/article.php/1335/Iris+Quartz
12th Jul 2017 05:57 UTCRob Woodside 🌟 Manager
13th Jul 2017 02:00 UTCSteven Kuitems Expert
13th Jul 2017 15:54 UTCRob Woodside 🌟 Manager
13th Jul 2017 16:47 UTCAlfredo Petrov Manager
13th Jul 2017 22:22 UTCJason Evans
I have just been examining my specimen with my microscope, it only has 20x magnification but I can see lamelar features, it's quite striking they look like tiny laser beams inside the crystal.
If I have understood it, or if i have misinterpreted what Rob said about his specimen these new findings appear to contradict Robs findings.
Thanks also the for kind comments about my photo, it is always nice when people appreciate the effort, especially when they know from experience that it is tricky to capture the iridescence on a still image.
17th Jul 2017 18:41 UTCRob Woodside 🌟 Manager
The array of high tech equipment brought to bear on this is quite impressive. Much of it looks at the surface which even Raman said was unimportant. Around fig 14 you can see separations inside the quartz which could be parting. In spite of their impressive technology they can't account for simple observations..
27th Sep 2017 13:51 UTCUwe Kolitsch Manager
Xiayang Lin and Peter J. Heaney (2017): Causes of iridescence in natural quartz. Gems & Gemology, 53, 68-81.
https://www.gia.edu/gems-gemology/spring-2017-iridescence-natural-quartz
(Added to quartz and iris quartz pages.)
27th Sep 2017 15:30 UTCJohn R. Montgomery 🌟 Expert
27th Sep 2017 23:26 UTCJason Evans
28th Sep 2017 02:24 UTCJohn R. Montgomery 🌟 Expert
Regards
John
28th Sep 2017 16:54 UTCRob Woodside 🌟 Manager
With a known fixed wavelength one could look for higher order diffraction peaks. That alone would prove the diffraction theory. A laser's intensity is needed to observe higher order peaks. (The fast Fourier Transform shown in Figure 13 in the Lin Heaney paper [thanks for the link Uwe] certainly hints at crude diffraction)
Using a fixed wavelength and the diffraction angles, one could have an independent measure of the "grating" spacing. This could then be used to predict the angles of diffraction peaks at different wavelengths and give a further check.Getting agreement between the published high tech grating and that found with a high intensity laser would be impressive..
It could be that both diffraction and thin film interference are at work here, but my simple observation of changing the colour by applying pressure shows that thin films are involved. Lin and Heaney say "The absence of either opal or compositional impurities definitively rules out iridescence by a thin-film effect, sensu stricto." and that is simply wrong. In xls with internal fractures there can be no compositional impurities and no opal like structures, but one does see the thin film interference colours in the fractures.
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Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: March 29, 2024 09:04:32