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Geology, Palaeontology & Archaeology / What is this branched pattern on a stone?
« on: 05/08/2018 07:52:48 »
Hi everyone,
My first post. I discovered this interesting forum while searching for an answer, never knew about it.
My family has the house you can see in the picture, with a layer of flat stones on the walls to avoid using paint because it is so close to the sea that it required repainting almost every year.
house.jpg (231.83 kB . 1024x682 - viewed 4516 times)
I don't know what that stone is, but it is natural and it sometimes "peels" off a layer that falls to the floor. If more info on this, is required, I'll do my best to answer. The question I am trying to clarify is not about that peeling off effect.
On cracks and the edges of those stones, it seems to grow this branched patter. Please find a pair of macro pictures I took. They cover around 10x10mm.They appear mostly on the south-facing wall. Note this part of Spain is very exposed to strong, direct sunlight and it is very humid, only a few meters from the sea.
10x10mm_clouseup2.jpg (228.33 kB . 1024x682 - viewed 4602 times)
You can see most are very dark branches but there are orange branches too. We thought about it being a fossil but discarded the idea when we found the branches grow a few milimetres every year. Then I though it was some kind of lichen, but I have been able to find a reference to a similar one.
10x10mm_clouseup1.jpg (297.86 kB . 1024x682 - viewed 7610 times)
My best guess for now it is some kind of oxidation or reaction that is formed on the surface of the stone that always starts on a crack or the edge of the stone and creeps following that pattern. Note the size of the branches is less than one millimetre. I brought home a corner of a rock that has a sample of that pattern and I looked at it under the microscope and it looks like paint.
I hope you find this interesting.
Thank you!
Roberto Barrios
My first post. I discovered this interesting forum while searching for an answer, never knew about it.
My family has the house you can see in the picture, with a layer of flat stones on the walls to avoid using paint because it is so close to the sea that it required repainting almost every year.
house.jpg (231.83 kB . 1024x682 - viewed 4516 times)
I don't know what that stone is, but it is natural and it sometimes "peels" off a layer that falls to the floor. If more info on this, is required, I'll do my best to answer. The question I am trying to clarify is not about that peeling off effect.
On cracks and the edges of those stones, it seems to grow this branched patter. Please find a pair of macro pictures I took. They cover around 10x10mm.They appear mostly on the south-facing wall. Note this part of Spain is very exposed to strong, direct sunlight and it is very humid, only a few meters from the sea.
10x10mm_clouseup2.jpg (228.33 kB . 1024x682 - viewed 4602 times)
You can see most are very dark branches but there are orange branches too. We thought about it being a fossil but discarded the idea when we found the branches grow a few milimetres every year. Then I though it was some kind of lichen, but I have been able to find a reference to a similar one.
10x10mm_clouseup1.jpg (297.86 kB . 1024x682 - viewed 7610 times)
My best guess for now it is some kind of oxidation or reaction that is formed on the surface of the stone that always starts on a crack or the edge of the stone and creeps following that pattern. Note the size of the branches is less than one millimetre. I brought home a corner of a rock that has a sample of that pattern and I looked at it under the microscope and it looks like paint.
I hope you find this interesting.
Thank you!
Roberto Barrios
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