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Interesting SEM images of gems at physicsforum
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Author:  norman [ Fri Nov 10, 2017 8:13 pm ]
Post subject:  Interesting SEM images of gems at physicsforum

Hi folks-

Been a long time since I was here much. However this topic caught my attention and I thought is worthy of the attention of the gemology folks here. And you all probably collectively can address their questions far more intelligently than I.

(I'm going to re-post this to a couple other sub-forums here; I simply want to get the right eyes on the pics- delete if appropriate!!)

https://www.physicsforums.com/threads/g ... as.930364/

Author:  Stephen Challener [ Sat Nov 11, 2017 12:56 am ]
Post subject:  Re: Interesting SEM images of gems at physicsforum

I would guess the emerald surface is mostly partially polished scratches left over from cutting, but that's kind of the easy way out on that.

The ruby dendrites are really strange. I'd guess it would have to be some (lovely) surface contamination--the orientation is just too perfect. You wouldn't really expect anything like that inherent in the structure since they crystallize relatively slowly and have plenty of time at relatively high temperatures for inclusions to take on more thermodynamically favorable configurations with a better surface area to volume ratio.

Author:  Peters [ Sat Nov 11, 2017 3:19 am ]
Post subject:  Re: Interesting SEM images of gems at physicsforum

Hi,
To be more objective with SEM images in high (10'000 - 100'000x) magnification, more info about SEM imaging condition needed: detector type, vacuum mode, acceleration voltage... very often, that kind of images is generated by surface charging, the best way to verify could be EDX mapping - BSE detector is less sensitive to element distribution than EDX.
Peters

Author:  norman [ Mon Nov 13, 2017 6:51 pm ]
Post subject:  Re: Interesting SEM images of gems at physicsforum

I've copy/pasted these comments over there. I'll let you know if we get more info.

THANKS!!

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