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UV MineralsCathodoluminiscence of minerals: simple demonstrations

22nd Mar 2019 20:31 UTCAdolf Cortel

Hi,

In the case somebody were interested in the subject of cathodoluminiscence I've uploaded a video in youtube on simple demonstrations of cathodoluminiscence of minerals. You'll see the setup and the results with some minerals.

The link is

https://youtu.be/Brq3aRRENgg

Here come some pictures (kunzite, sheelite and calcite+willemite)

22nd Mar 2019 21:38 UTCDon Saathoff Expert

Adolf, very nice video!! AND very nice musical accompaniment!!! Wasn't that Joan Chamoro's St. Andreau School Jazz Band?!? An amazing group of children!!!

Don S.

22nd Mar 2019 22:13 UTCAdolf Cortel

Hi Don. Thanks for your kind comment. Of course it is Joan Chamorro's troupe! Their version of Mood Indigo is amazing; I hope that youtube won't enforce me to remove the music because of copyright issues.

22nd Mar 2019 22:53 UTCDon Saathoff Expert

I'm definitely on your side! Chamorro has done an unbelievable job with those kids.....Jazz is not dead!! (Neither is cathodoluminescence !!).

23rd Mar 2019 10:36 UTCRoger Curry

Hi Adolf,
Excellent project!! Have you tried fluorite? I'd be VERY interested to see how the cathode rays excite North Pennines fluorite crystals. They show a variety of colours, in many examples zones of different colours appear as phantoms. If such a crystal was cut across these zones of colour, perhaps cathodoluminescence would show something of interest. The colouration and zoning of Weardale fluorite is an interest of mine, see here.

If you'd pay post and packing I'd gladly send you some examples from Heights mine, to do with what you like.

Cheers,

Rog

23rd Mar 2019 12:38 UTCAdolf Cortel

Hi Roger,

What I have done is only for demonstration purposes. As you know, cathodeluminiscence is used widely in SEM to check zonation but they use accelerating voltages much larger, 20kV or more (I'm using only 2 kV!. My only advantage is that this makes this demonstrations safe regarding the possible emission of X-ray, because at this low energy they do not go trough the glass of the tube, but this restricts a lotf what can be seen. Particularly, the low penetration of electrons excite the luminiscente only in the surface of the mineral

At this low voltage the samples of fluorite I have tried (from Papiol and Singuerlin, which fluoresce strongly in LW) give only a very dim violet glow. In some cases the cathodeluminiscence I see in my setup is similar to what is observed when looking under SW UV (these fluorites from Papiol or Singerlin do not fluoresce at SW). Regarding the zonated fluorites you refer I'm sure that the appropiate technique to check the correlation between composition and luminiscence or color is SEM or a dedicated cathodoluminiscence apparatus

Best regards,

Adolf

23rd Mar 2019 14:10 UTCRoger Curry

Hi Adolf,

Just had a chance to look at your youtube channel, highly impressive! Don't forget the offer of free specimens, should you return to cathodoluminescence experimentation,

Regards,

Rog

23rd Mar 2019 16:21 UTCAdolf Cortel

Thanks a lot for your offer Roger. In the case I manage better tools to study cathodoluminiscence I'll get in touch with you!

Adolf

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