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Fluorite threelobes
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Author:  75TURBO [ Tue Sep 19, 2017 5:29 am ]
Post subject:  Fluorite threelobes

HI,

I own some violet cabs: at first look, they look like amethyst.
Image
After investigation, S.G. and R.I. (spot reading) are in the range of fluorite.
Under LW UV the stones are fluorescent and at 130°C they are thermoluminescent.

Under microscope, the color zoning are different from the others fluorite I have seen.
Image

I mean color zones are in the shape of "threelobes".
Image
A little help:
Image

Image

Any comment will welcome.

Author:  Stephen Challener [ Tue Sep 19, 2017 3:26 pm ]
Post subject:  Re: Fluorite threelobes

'Mercedes logo' zoning is sometimes seen at larger scales in fluorite, particularly Illinois ones. Here's one from Spirifer minerals:
Image
I've never seen them at this scale though--that's really interesting!

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