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RheinSte
Joined: 13 Aug 2024
Posts: 3
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 Posted: Aug 14, 2024 12:59 Post subject: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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Hello folks!
Recently I have seen a specimen but the owner has not yet confirm the identity of the purple crystal that grow out from the base of this smoky skeletal quartz. The origin of this specimen might be Madagascar. The guess about this crystal is tourmaline, but purple tourmaline is usually a rare case.
I appreciate any insights you can provide.
| Dimensions: | 1.8cm*0.5cm*0.5cm |
| Description: |
| the stated dimension is of the purple mineral only |
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Matt_Zukowski
Site Admin
Joined: 10 Apr 2009
Posts: 715
Location: Alaska
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| Posted: Aug 14, 2024 13:33 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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| Could be apatite. Are there and small broken xtals that you can remove and use for harness, etc tests?
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4919
Location: Barcelona
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| Posted: Aug 14, 2024 14:00 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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| RheinSte wrote: | | ...but purple tourmaline is usually a rare case... |
Matt is right; it could be Apatite, but Fluor-liddicoatite can also have a similar purple color.
| Mineral: | Fluor-liddicoatite with Quartz |
| Locality: | | Sahatany Valley (Mt. Ibity), Vakinankaratra Region, Antananarivo Province, Madagascar |  |
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| Dimensions: | 2.5 × 1.7 × 1.3 cm |
| Description: |
| Specimen and photo: #MVM (Minerals - Virtual Museum) |
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| Mineral: | Fluor-liddicoatite |
| Locality: | | Sahatany Valley (Mt. Ibity), Vakinankaratra Region, Antananarivo Province, Madagascar | |
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| Dimensions: | 2.5 × 1.7 × 1.3 cm |
| Description: |
Top of the same specimen
Specimen and photo: #MVM (Minerals - Virtual Museum) |
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1352 Time(s) |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1189
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| Posted: Aug 14, 2024 14:35 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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Sorry, Jordi,
I see a ternary axis. So it's a tourmaline, which is not unusual for the locality
probably Mount Ibity Area.
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4919
Location: Barcelona
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| Posted: Aug 14, 2024 15:45 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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| Roger Warin wrote: | Sorry, Jordi,
I see a ternary axis. So it's a tourmaline, which is not unusual for the locality
probably Mount Ibity Area. |
Not to contradict you, Roger, but Fluor-liddicoatites, being members of the Tourmaline group, belong to the trigonal crystal system, which indeed has a ternary axis.
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RheinSte
Joined: 13 Aug 2024
Posts: 3
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| Posted: Aug 19, 2024 21:14 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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| Unfortunately, I cannot request any destructive tests from the owner. However, he appears to be interested in an analytical test that will be available in his city in the coming days. Hopefully, he will send the sample there, and I will receive the answer by then
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RheinSte
Joined: 13 Aug 2024
Posts: 3
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| Posted: Aug 28, 2024 04:12 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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NEW UPDATE:
The owner sent the specimen for Raman spectroscopy analysis. The spectrum indicates the purple mineral is Amethyst.
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Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 832
Location: Northeast Ohio
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| Posted: Aug 28, 2024 14:11 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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I am sorry, but I think it is very unlikely that the purple prism is amethyst. Perhaps there is a thin film of quartz on the purple mineral that gave a deceptive reading.
_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1189
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| Posted: Aug 28, 2024 14:59 Post subject: Re: what is this? A purple tourmaline grown out from the base of a skeletal quartz? |
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I am surprised by these hesitations.
It seems obvious to me that the morphology of this crystal and its appearance say that it is a tourmaline.
I think it is Malagasy.
The distinction between the 2 species elbaite / liddicoatite is not obvious. Both species are present.
It is true that in the past liddicoatites made Madagascar and the Mount Ibi region famous.
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