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The information provided within this Forum about localities is only given to allow reference to them. Any visit to any of the localities requires you to obtain full permission and relevant information prior to your visit. FMF is strictly against any illicit activities related to collecting minerals.
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| Search found 784 matches |
| Author | Message |
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 Topic: Libyan Desert Glass Structure |
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| alfredo Replies: 60 Views: 90876 |
 Forum: Minerals and Mineralogy Posted: Jul 01, 2025 14:47 Subject: Re: Libyan Desert Glass Structure |
| Marco wrote: " you cannot hunt for fossils inside a glass that was formed at temperatures estimated to be above 2750°C. If the rocks around the impact have been sublimated you cannot find any tra ... | |
| Topic: Preparing a list of light sensitive minerals - (14) |
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| alfredo Replies: 97 Views: 215825 |
Forum: Featured Columns of FMF Posted: May 21, 2025 16:53 Subject: Re: Preparing a list of light sensitive minerals - (14) |
| José Angel, In the case of your coquimbite turning brown, it is not the light but rather the dryness that is the problem. Coquimbite is only stable at atmospheric humidities between 30 < 70 %. Drie ... | |
| Topic: Star Quartz |
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| alfredo Replies: 3 Views: 5308 |
Forum: Micros & Macros - Images of Minerals Posted: Apr 19, 2025 11:21 Subject: Re: Star Quartz |
| This is a piece of star quartz I got at the Prague show several years ago. Seems to have started growth as quartz with red hematite inclusions, and later continued growth as yellow quartz with probabl ... | |
| Topic: cristobalite vs chalcedony in thin section |
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| alfredo Replies: 16 Views: 21169 |
Forum: Minerals and Mineralogy Posted: Apr 09, 2025 13:18 Subject: Re: cristobalite vs chalcedony in thin section |
| Hi Alfredo,
perhaps you are referring to the gypsum of Mina Rica, Pulpì, Almeria... Hi Marco, No, I have never been to Pulpi, or anywhere else in Almería. Definitely gypsum beds in Archidona, wh ... |
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| Topic: cristobalite vs chalcedony in thin section |
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| alfredo Replies: 16 Views: 21169 |
Forum: Minerals and Mineralogy Posted: Apr 08, 2025 21:34 Subject: Re: cristobalite vs chalcedony in thin section |
| Thank you, gentlemen, for this interesting discussion. I observed very similar looking millimeter-size spherules in gypsum in Archidona, Spain: https://www.mindat.org/loc-257672.html - and I had been ... | |
| Topic: Wulfenite and Mimetite |
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| alfredo Replies: 17 Views: 191308 |
Forum: Micros & Macros - Images of Minerals Posted: Apr 06, 2025 01:29 Subject: Re: Wulfenite and Mimetite |
| You don't need acid to dissolve fluorite, because fluorite is very slightly soluble in plain water! ...a few tens of milligrams per liter of water. So if you put a fluorite crystal into running water, ... | |
| Topic: Wulfenite and Mimetite |
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| alfredo Replies: 17 Views: 191308 |
Forum: Micros & Macros - Images of Minerals Posted: Apr 04, 2025 19:09 Subject: Re: Wulfenite and Mimetite |
| "the limonite is not replacing the fluorite, so not a pseudomorph"
Some pseudomorph collectors would disagree with this statement and would consider these "moulds" to be one of ... |
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| Topic: Libyan Desert Glass Structure |
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| alfredo Replies: 60 Views: 90876 |
Forum: Minerals and Mineralogy Posted: Mar 19, 2025 11:54 Subject: Re: Libyan Desert Glass Structure |
| Sorry, I just accidentally deleted someone's post here. If it was yours, please re-post it. The post appeared double on my screen, so I wanted to remove the duplicate, but they both disappeared. Must ... | |
| Topic: Libyan Desert Glass Structure |
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| alfredo Replies: 60 Views: 90876 |
Forum: Minerals and Mineralogy Posted: Mar 18, 2025 03:10 Subject: Re: Libyan Desert Glass Structure |
| Marco, thank you for this very interesting explanation.
I'm wondering what you mean by "anhydrous" magma yielding obsidian, because obsidian does contain a little bit of water. One common ... |
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| Topic: Is there a metaphysical properties section to this forum? |
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| alfredo Replies: 2 Views: 2631 |
Forum: Off-Topic and Introductions Posted: Mar 03, 2025 14:37 Subject: Re: Is there a metaphysical properties section to this forum? |
| Metaphysical properties exist only in the human imagination (and I can offer PROOF of this if desired), so I really hope we don't start discussing that in this forum. | |
| Topic: It's Tucson Time Again - 2025 |
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| alfredo Replies: 110 Views: 49439 |
Forum: News about Shows Posted: Feb 03, 2025 16:44 Subject: Re: It's Tucson Time Again - 2025 |
| Not letting producers know what final retail prices are may well be the reason for dealers wanting prices to be blocked out on show reports, but it is a rather silly and useless exercise, because nowa ... | |
| Topic: Unknown from Tsumeb |
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| alfredo Replies: 11 Views: 4338 |
Forum: FOR BEGINNERS: What is it? Where is it from? Posted: Jan 30, 2025 23:23 Subject: Re: Unknown from Tsumeb |
| "Would an elemental analysis by EDX be enough.?"
In my experience, EDX does a poor job with light elements like Mg and C. So unless you are performing the analysis on a flat polished surf ... |
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| Topic: Limonitized garnet? |
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| alfredo Replies: 36 Views: 13070 |
Forum: What is it? - Where is it from? Posted: Jan 27, 2025 00:31 Subject: Re: Limonitized garnet? |
| Roger, I don't think you can insist that Fleischer's glossary should include more than what it states to be its intent: a list of species. So anything that is not a "species" won't be includ ... | |
| Topic: Limonitized garnet? |
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| alfredo Replies: 36 Views: 13070 |
Forum: What is it? - Where is it from? Posted: Jan 26, 2025 18:20 Subject: Re: Limonitized garnet? |
| "Limonite" is a field term for iron oxides which have not been analyzed and for which the species is not known, although 90% of the time it is either goethite or a mixture of hematite and go ... | |
| Topic: Limonitized garnet? |
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| alfredo Replies: 36 Views: 13070 |
Forum: What is it? - Where is it from? Posted: Jan 23, 2025 15:59 Subject: Re: Limonitized garnet? |
| What I meant was that the fact that a mineral occurs at all in large quantities in alluvium means that that mineral is not very susceptible to chemical or physical weathering. In other words it is a t ... | |
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