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Dany Mabillard
Joined: 01 Jul 2019
Posts: 357
Location: Valais
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 Posted: Aug 09, 2020 09:33 Post subject: Calcite ? |
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Hello everybody,
I need some help to identify this mineral if it is one, found in Mellikon, Argovie, Switzerland.
Thank you in advance for the time you'll take to answer me.
Have a nice day.
Best regards.
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Mellikon, Argovie, Switzerland
130 mm x 90 mm x 50 mm |
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6866 Time(s) |
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vic rzonca
Joined: 18 Nov 2008
Posts: 820
Location: MA
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| Posted: Aug 09, 2020 11:27 Post subject: Re: Calcite ? |
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| Dany, you might try an acid test on a bit of the unknown, possibly scraped from an in-obvious place. Put a few drops of lemon juice on it. If it fizzes, combined with the location, would indicate limestone.
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2249
Location: Oklahoma
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| Posted: Aug 09, 2020 11:36 Post subject: Re: Calcite ? |
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Dany,
Mindat lists Mellikon as a quarry in Jurassic limestones. My guess is that you will find an acid test yields positive results indicating a carbonate. Your specimen looks to me like a calcite or limestone replacement of coral.
Michael
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SteveB
Joined: 12 Oct 2015
Posts: 239
Location: Canberra
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| Posted: Aug 10, 2020 00:30 Post subject: Re: Calcite ? |
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| Looks like a coated coral, likely fossilised with outer coating of calcite, possibly chalk. The smoothness is unnatural for Coral. But there are indications is not waterworn and crusty cavities I expect you will find tiny crystal growth If you examine under magnification. Examination of the breakage underneath may also help. It may show deposition rings to help out.
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Dany Mabillard
Joined: 01 Jul 2019
Posts: 357
Location: Valais
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| Posted: Aug 10, 2020 12:08 Post subject: Re: Calcite ? |
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Thank you Michael, Vic and Steve for your answers. I will do the test and investigations next weekend when I can access the specimen.
Have a nice week.
Dany.
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Riccardo Modanesi
Joined: 07 Nov 2011
Posts: 631
Location: Milano
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| Posted: Aug 11, 2020 03:14 Post subject: Re: Calcite ? |
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Hi to everybody!
Yes, I agree with Steve: in my opinion it's a fossil coral. The area is well known both for corals and for ammonites and nautiloids. Some corals DO have this aspect.
Greetings from Italy by Riccardo.
| SteveB wrote: | | Looks like a coated coral, likely fossilized with outer coating of calcite, possibly chalk. The smoothness is unnatural for Coral. But there are indications is not waterworn and crusty cavities I expect you will find tiny crystal growth If you examine under magnification. Examination of the breakage underneath may also help. It may show deposition rings to help out. |
_________________
Hi! I'm a collector of minerals since 1973 and a gemmologist. On Summer I always visit mines and quarries all over Europe looking for minerals! Ok, there is time to tell you much much more! Greetings from Italy by Riccardo. |
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Dany Mabillard
Joined: 01 Jul 2019
Posts: 357
Location: Valais
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| Posted: Aug 16, 2020 10:08 Post subject: Re: Calcite ? |
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Thank you all for your answer. I tried with the lemon in the back where it's like the front without success but maybe I haven't done correctly. In the back, the whiter part seems to be Chalk (1 in the moh's scale). I put 2 photos from the back
Have a nice day.
| Locality: | | Switzerland |  |
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vic rzonca
Joined: 18 Nov 2008
Posts: 820
Location: MA
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| Posted: Aug 16, 2020 10:34 Post subject: Re: Calcite ? |
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| Dany Mabillard wrote: | Thank you all for your answer. I tried with the lemon in the back where it's like the front without success but maybe I haven't done correctly. In the back, the whiter part seems to be Chalk (1 in the moh's scale). I put 2 photos from the back
Have a nice day. |
Well, you have a result to your test. May be your technique or it may be negative for carbonate. Your hardness test adds to the "knowns" as Donald Rumsfeld might say. It looks to have several minerals in bits or in layers. It seems fossiliferous. :-)
| Mineral: | Brain coral, dried, non-fossilized.There are many types. |
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