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Identity HelpWhat is On and In this Fluorite?

5th Mar 2017 16:32 UTCBrian Greenstone

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This giant pink fluorite tetrahedron is from the Huanggang Mine in China. I need a little help identifying two things:


1. The white substance on the outside. It's soft and chalky. Calcite? Dolomite?


2. The things on the face of the fluorite that look like scratches are not scratches; they're hair-like inclusions in the fluorite itself and they go deep into it. I have no idea whatsoever what those could be. Any ideas?


Thanks,


-Brian


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02123830015659822041711.jpg

5th Mar 2017 16:39 UTCBrian Greenstone

Oh, one other thing... I know those hairs look like Boulangerite, but the hairs are white and the only Boulangerite examples I've seen are always black, so that makes me think its something else.


-Brian

5th Mar 2017 17:32 UTCBob Harman

I know little of Chinese fluorites, but here in the sedimentary Midwest , white chalky coatings are commonly the clay minerals. Could yours be Kaolinite? CHEERS.....BOB

5th Mar 2017 17:41 UTCReiner Mielke Expert

First of all it is an octahedron not a tetrahedron. Clay minerals strongly absorb water so if your tongue sticks to it, it is probably a clay mineral. Those hairs could be inclusions of byssolite.

5th Mar 2017 18:03 UTCPavel Kartashov Manager

Such white coatings also may to turn out some alumofluoride (gearksutite or prosopite). Hairs able to be empty channels within fluorite.

5th Mar 2017 19:19 UTCHolger Hartmaier 🌟

Is this a real specimen? It looks like it came out of a mold. Looks too perfect. Explain the smooth edges of the white matrix material around the bottom and right side of the crystal.

5th Mar 2017 19:21 UTCBrian Greenstone

Yes, it's definitely real. There are even casts in the mystery white material where other small fluorite octahedrons were. The face of the fluorite you see has been polished to look that way. Otherwise, the entire thing would have been covered in the white stuff.


-Brian

5th Mar 2017 22:26 UTCGregg Little 🌟

The white encrusting material looks almost too even all around although it could have been shaped just as one face has been polished. I did not see if Brian tried dilute HCl on the encrusting material; that would help in the identification.

6th Mar 2017 00:31 UTCBrian Greenstone

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Here's a closer look. I think the white stuff simply grew around the fluorite, and then apparently some smaller fluorite crystals grew on that which later fell off as you can see by the casts.


-Brian

02592520017055978534291.jpg

7th Mar 2017 07:31 UTCEligiusz Szełęg Expert

In my opinion clay minerals on and bavenite in fluorite.

Regards

Elek
 
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