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marco campos-venuti Replies: 60 Views: 95294 |
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I see epigenetic inclusions in LDG_14, not leaves. | |
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marco campos-venuti Replies: 60 Views: 95294 |
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An impression is a fossil.
Absolutely not. And first of all you have to demonstrate the impression of what it is. I do not see any biological structure in your "impressions". |
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marco campos-venuti Replies: 60 Views: 95294 |
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The presence of carbon and some organic molecules does not mean that they are fossils. No primary biological structure has been found. | |
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marco campos-venuti Replies: 60 Views: 95294 |
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Still the ignition temperature of a seed is in the order of 2-300 C and melting point of glass is around 800 C. | |
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marco campos-venuti Replies: 60 Views: 95294 |
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Dear Craig, I admire the perseverance and illusion you put into your study.
However, you cannot hunt for fossils inside a glass that was formed at temperatures estimated to be above 2750°C. If the ro ... |
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marco campos-venuti Replies: 3 Views: 1244 |
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Dear Roger and Pete, thank you for your comments. The title of the post was intentionally provocative. However, I would like to open the controversy.
Mindat clearly says that "any gwindel is nec ... |
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marco campos-venuti Replies: 3 Views: 1244 |
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A curiosity I found in Sainte Marie this year. This skutterudite crystal from Bou Azzer is twisted. It was a typical Moroccan lot consisting of a box with at least 30 crystals and all of them showed t ... | |
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marco campos-venuti Replies: 7 Views: 2951 |
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I show you the back of the cabochon made of white opal. The dendrite is all inside. This is the drawer where it has been for 13 years. The only change was the addition of the azurite and malachite sam ... | |
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marco campos-venuti Replies: 7 Views: 2951 |
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Years ago I cut a beautiful clear opal cabochon with a beautiful well-centered black dendrite. The best quality of that cabochon was that it was from Cabo de Gata, Almeria, Spain a little-known locati ... | |
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marco campos-venuti Replies: 16 Views: 22329 |
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Sorry Alfredo,
my comment comes from the fact that gypsum does not appear on the mindat page. Maybe you can add it. |
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marco campos-venuti Replies: 16 Views: 22329 |
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Hi Alfredo,
perhaps you are referring to the gypsum of Mina Rica, Pulpì, Almeria, Spain, where gypsum crystals show inclusions of celestine needles and white spherulites. In my opinion, in that case ... |
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marco campos-venuti Replies: 16 Views: 22329 |
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Hi Daniel,
From the hand sample the chalcedony is spherical and I don't see any faces. From the last photo you can see chalcedony filling a cavity inside a gypsum crystal, but I still don't see any f ... |
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marco campos-venuti Replies: 16 Views: 22329 |
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I don't see replacing after gypsum. The formation of your spherulites looks like the growth of a concretion. There is a granular gypsum with porosity. A Si-rich solution flows through the porosity. Th ... | |
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marco campos-venuti Replies: 16 Views: 22329 |
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My impression is that it is all chalcedony. Chalcedony is a fibrous silica polymer so the structure you see in thin section looks very similar to it. Cristobalite is stable over 1470ºC, Therefore it i ... | |
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marco campos-venuti Replies: 16 Views: 22329 |
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Cristobalite is high T mineral. All supposed cristobalite spherulites are other silica phase. | |
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