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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 108 matches |
| Author | Message |
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 Topic: Tourmaline - Quartz epitaxy? |
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| marco campos-venuti Replies: 7 Views: 987 |
 Forum: Minerals and Mineralogy Posted: Apr 23, 2022 06:02 Subject: Re: Tourmaline - Quartz epitaxy? |
| The pocket contained several hundred crystals, all with their respective tourmaline in the center and with the same orientation. I had the opportunity to measure some of them and they all gave values ... | |
| Topic: Forms Involved in Titanite Crystal |
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| marco campos-venuti Replies: 19 Views: 3130 |
Forum: Minerals and Mineralogy Posted: Apr 22, 2022 14:58 Subject: Re: Forms Involved in Titanite Crystal |
| I have an untwinned single crystal of titanite from that area. I had it as from Mohmand Agency, Pakistan, not really near, but you know stones in these mountains walk with nomad peoples. It has many s ... | |
| Topic: Tourmaline - Quartz epitaxy? |
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| marco campos-venuti Replies: 7 Views: 987 |
Forum: Minerals and Mineralogy Posted: Apr 22, 2022 14:12 Subject: Re: Tourmaline - quartz epitaxy? |
| In a paper published years ago, I suggested the possibility of quartz epitaxy after tourmaline at an angle of 23.5°. I took these data from a group of quartz crystals probably found in Morro Redondo, ... | |
| Topic: Minerals and mysteries from a college collection |
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| marco campos-venuti Replies: 9 Views: 2935 |
Forum: What is it? - Where is it from? Posted: Oct 20, 2021 06:20 Subject: Re: Minerals and mysteries from a college collection |
| There are many minerals making nodules with the same fabric. Barite also is a good guess, you can check density. | |
| Topic: April shows in Tucson?? |
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| marco campos-venuti Replies: 10 Views: 6874 |
Forum: Mineral Shows by Gail Spann Posted: Dec 16, 2020 12:26 Subject: Re: April shows in Tucson?? |
| GJX is not planning on having an April show as they "feel things won’t be much different than they are now". | |
| Topic: Interesting find, opalized scoria from oregon |
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| marco campos-venuti Replies: 1 Views: 2206 |
Forum: What is it? - Where is it from? Posted: Sep 18, 2020 05:31 Subject: Re: Interesting find, opalized scoria from oregon |
| Scorias are often filled by silica because cavities drain water. It is difficult to find empty cavities in old scorias from the geological record. More often they are filled by something, zeolites, ca ... | |
| Topic: Quartz and Humboldtine? from Colombia |
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| marco campos-venuti Replies: 16 Views: 16975 |
Forum: Minerals and Mineralogy Posted: Oct 07, 2018 12:20 Subject: Re: Quartz and Humboldtine? from Colombia |
| I bought this in 2006, supposedly from Brazil. It looks so similar!
Here the yellow appears to be inside. The vermicular growth reminds me of chlorite family minerals. The yellow is brighter in real ... |
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| Topic: Who to trust with gemstone identification? Are some gemologists better than others? |
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| marco campos-venuti Replies: 11 Views: 16295 |
Forum: Incorrect classification and fakes Posted: Sep 07, 2018 06:28 Subject: Re: Who to trust with gemstone identification? Are some gemologists better than others? |
| The distinction from natural citrine and heat treated amethyst is possible with expensive test in a high tech laboratory. Because citrine is a cheap stone, dealers assume all citrine in the market are ... | |
| Topic: Termination in a tourmaline crystal |
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| marco campos-venuti Replies: 2 Views: 4800 |
Forum: Minerals and Mineralogy Posted: Aug 28, 2018 08:37 Subject: Termination in a tourmaline crystal |
| I had this green tourmaline crystal on a recent trip to Brazil. It comes from Barra de Salinas pegmatite. It seems to me a quite unusual termination. Most of crystals from pegmatites have a lower symm ... | |
| Topic: Abrasives repairing polishing crystals |
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| marco campos-venuti Replies: 11 Views: 11101 |
Forum: Conserving, Preparing and Cleaning Minerals Posted: Aug 18, 2018 17:34 Subject: Re: Abrasives repairing polishing crystals |
| Of course natural is better as for hair, nose, breast, etc. But in some cases you want to save a specimen. Because of sentiment, because it is very valuable or because it is an educational specimen. I ... | |
| Topic: Agates in Sicily? |
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| marco campos-venuti Replies: 9 Views: 17232 |
Forum: Rockhounding trips Posted: Apr 25, 2018 11:16 Subject: Re: Agates in Sicily |
| Bad News Alan, no agates in Sicily!!!
Despite the tradition wants that the name agate comes from the old name of the Drillo River, a small creek passing near Etna Volcano, there was probably a big hi ... |
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| Topic: Faden Quartz Crystals - (26) |
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| marco campos-venuti Replies: 63 Views: 84025 |
Forum: Featured Columns of FMF Posted: Dec 15, 2017 11:28 Subject: Re: Faden Quartz Crystals - (26) |
| Hi Roger,
I consider we are at the same side of the theories, as anti-official. But something in your discussion sounds strange to me. A gel is a solid and for that reason can't have viscosity that ... |
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| Topic: Information about a Rhodochrosite specimen |
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| marco campos-venuti Replies: 3 Views: 6603 |
Forum: Minerals and Mineralogy Posted: Nov 18, 2017 09:16 Subject: Re: Information about a Rhodochrosite specimen |
| Check mindat:
https://www.mindat.org/photo-519101.html Wutong Mine (Wudong Mine), Liubao, Cangwu Co., Wuzhou Prefecture, Guangxi Zhuang Autonomous Region, China |
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| Topic: Micro photos of inclusions in Quartz |
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| marco campos-venuti Replies: 108 Views: 103461 |
Forum: Micros & Macros - Images of Minerals Posted: Nov 14, 2017 06:50 Subject: Re: Micro photos of inclusions in Quartz |
| I have one sample of the blue inclusion. I'm not sure it is natural or synthetic quartz. No info about any deposit. | |
| Topic: Super thin hematite inclusions in amethyst |
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| marco campos-venuti Replies: 22 Views: 25034 |
Forum: Micros & Macros - Images of Minerals Posted: Nov 13, 2017 04:21 Subject: Re: Super thin hematite inclusions in amethyst |
| It is from Rome!
(We are joking, come back to the topic please) |
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| Topic: Super thin hematite inclusions in amethyst |
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| marco campos-venuti Replies: 22 Views: 25034 |
Forum: Micros & Macros - Images of Minerals Posted: Nov 12, 2017 12:44 Subject: Re: Super thin hematite inclusions in amethyst |
| And here is what we call Quartz with iron oxides, because we don't know what it really is. Also from Minas Gerais | |
| Topic: Super thin hematite inclusions in amethyst |
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| marco campos-venuti Replies: 22 Views: 25034 |
Forum: Micros & Macros - Images of Minerals Posted: Nov 12, 2017 12:41 Subject: Re: Super thin hematite inclusions in amethyst |
| And here few examples of what I consider Goethite in Quartz. I'm not sure, just is what I use to call it. Mostly yellow and strictly fibrous, more abundant in Amethyst. All samples from Brazil.
The l ... |
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| Topic: Super thin hematite inclusions in amethyst |
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| marco campos-venuti Replies: 22 Views: 25034 |
Forum: Micros & Macros - Images of Minerals Posted: Nov 12, 2017 12:31 Subject: Re: Super thin hematite inclusions in amethyst |
| Few examples of what I suppose is Hematite in Quartz. Mostly red, main characteristic is a flat crystal, more or less elongated.
All sample are from Brazil, difficult to say the exact place. How woul ... |
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| Topic: Super thin hematite inclusions in amethyst |
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| marco campos-venuti Replies: 22 Views: 25034 |
Forum: Micros & Macros - Images of Minerals Posted: Nov 12, 2017 12:18 Subject: Re: Super thin hematite inclusions in amethyst |
| John, is it possible to distinguish fibrous Hematite from fibrous Goethite with the naked eye? I mean not included in quartz but when they are in botryoidal shape. I suspect there is a bit of confusio ... | |
| Topic: Rarest quartz twins with inclined axes C |
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| marco campos-venuti Replies: 42 Views: 41387 |
Forum: Minerals and Mineralogy Posted: Nov 08, 2017 20:27 Subject: Re: Rarest quartz twins with inclined axes C |
| I think auto-epitaxy is a synonym of twinning. Epitaxy is between two different minerals.
If a secondary xl (or a epitaxial film) grows over a main xl, its atoms will continue the lattice of the firs ... |
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