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Auteur Topic: What is this mineral?  (gelezen 1178 keer)

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giugphix

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What is this mineral?
« Gepost op: april 20, 2017, 16:45:18 »
Hello to all, i'm new here!
Can you help me to determinate this mineral?

giugphix

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Re: What is this mineral?
« Reactie #1 Gepost op: april 20, 2017, 16:55:25 »
here

Daniel Middel

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Re: What is this mineral?
« Reactie #2 Gepost op: april 20, 2017, 17:11:23 »
Hi welcome to the forum. Where did you find this exactly?
Based on just pictures I'd say yellow Calcite.

giugphix

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Re: What is this mineral?
« Reactie #3 Gepost op: april 20, 2017, 17:26:42 »
i was thinking Calcite to, but professor saied me that this is not calcite. this is much heavy to be Calcite. I'dont succed to line/rule with my finger nail, but i succed with a steel blade. So i suppose isn't quarz

Daniel Middel

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Re: What is this mineral?
« Reactie #4 Gepost op: april 20, 2017, 20:38:33 »
If it is heavy it can also be Baryte which is heavier because of the Barium. Where did you find it?

giugphix

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Re: What is this mineral?
« Reactie #5 Gepost op: april 20, 2017, 21:20:08 »
i don't know where this mineral have been find , i'live in Sardinia(Italy), but i don't know if was in my land.

Niels Brouwer

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Re: What is this mineral?
« Reactie #6 Gepost op: april 21, 2017, 10:44:30 »
I agree with Daniel, it's definitely baryte. It is quite typical for the brownish-yellow barytes that come from Villamassargia,
 Fluminimaggiore or the surrounding area on Sardinia.

giugphix

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Re: What is this mineral?
« Reactie #7 Gepost op: april 21, 2017, 11:19:24 »
But is this one crystal or an aggregate/united of crystals? is possible for baryte to have so close and so perfect prisms and flaking ?
yes the axis seem to be crossing to gether with 90 angles.
 
So Thank you very much for help me.

Niels Brouwer

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Re: What is this mineral?
« Reactie #8 Gepost op: april 21, 2017, 19:12:26 »
Yes, baryte can certainly have very distinct colour zoning and internal fractures like this. In fact, many of these larger Sardinian crystals show exactly this effect. I have a few in my collection that show exactly the same effect. I also think it's one continuous crystal structure rather than an aggregate in which multiple crystals grew together, although that's a little difficult to judge from only these photos.
The 90 angle is visible in your second photo, as you rightly point out. This shows the crystal system is orthorhombic, whereas calcite would not have this right angle as it's trigonal.

Henk Smeets

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Re: What is this mineral?
« Reactie #9 Gepost op: april 30, 2017, 13:02:13 »
Looks much more like vesuvianite... but without knowing where it comes from it is nearly impossible to determine it with confidence.
Henk Smeets

Robin Bakker

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Re: What is this mineral?
« Reactie #10 Gepost op: april 30, 2017, 17:59:10 »
Hi,

Both Baryte and Calcite can appear blocky.. so why not just test with acids to be sure? It's a very simple test: drop a little bit of hydrochloric acid on the sample and watch for bubbles. If you don't have access to hydrochloric acid, you could try it with some strong vinegar ("cleaning vinegar"). That should also work fine. If in doubt look with a magnifier.
Having said that, based on the photos and the information you have given (heavy) I would also tend to go with Baryte.

Robin
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p_slootweg

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Re: What is this mineral?
« Reactie #11 Gepost op: mei 02, 2017, 14:01:56 »
Baryte for sure!