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Coral? or just stone?


salvo1989s

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Hi, my brother sent me this stone that he found on a beach in sicily (taormina) can this be a fossil coral? or its just volcanic stone? 

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Volcanic rock I think, given the location (would have said slag for other places). I can't see any coral structure.

Tarquin

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Looks more like a pebble with bivalve borings.

 

p1160455ablog7.jpg.124252ba20de50e0e13511272e7b7a34.jpg

picture from here

 

Interestingly, there are also nice worm tube remains in some of the holes.

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

Thomas Mann

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10 minutes ago, abyssunder said:

Looks more like a pebble with bivalve borings.

 

p1160455ablog7.jpg.124252ba20de50e0e13511272e7b7a34.jpg

picture from here

 

Interestingly, there are also nice worm tube remains in some of the holes.

 

Could well be, but there are a lot of much smaller holes too. Different organisms perhaps.

Tarquin

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Volcanic rock.

Corals have a regular structure, in that the "holes" (which are openings to tubes called corallites, each one of which housed a single coral animal in the colony) are uniform in their size and spacing.  Also, corallites will have internal structures including septa.  In your specimen, the holes are completely irregular in size and spacing, they do not appear to be openings to tubes but instead are rounded cavities, and they lack any sign of internal structures.  Some volcanic rocks are full of bubbles that form when gases come out of solution as the lava cools; the extreme is pumice, which is so full of bubbles it can float on water.

 

I don't think the holes are bivalve borings, either.  Some holes appear to expand as they go into the rock, and at least one (along the midline of the rock, towards the left side) has an irregularly shaped perforation that opens into another cavity deeper in the rock, as if the thin wall between bubbles has been broken through.  Overall, the holes look like random sections through irregularly shaped bubbles in the rock, not openings to tubes like bivalve borings.  Also the rock itself has a texture like igneous rock, though that is of course hard to determine with complete confidence from a photo.

 

Don

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Vesicular volcanic rocks,like fossildawg says ,the holes are from ebullition of volatiles

 

 

 

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In the "big" holes i see smaller ones, as if it has been semi-liquid at one time, so i'll go with the volcanic rock camp. It's an interesting stone.:)

theme-celtique.png.bbc4d5765974b5daba0607d157eecfed.png.7c09081f292875c94595c562a862958c.png

"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

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I dont know what kind of rock could it be, but I think a better resemblance of the holes is with sponge borings rather than pholadid borings. All the boring types (mechanical, chemical) have irregular distribution on a rock surface. More details here .

 

" Typically a pebble or shell that has been affected by this kind of sponge infestation will have a series of regular-shaped circular holes on the surface. These holes may cover the entire surface of the object in severe infestation. Sometimes there are only a few holes when the sponge is just starting to colonise the pebble. These may appear as a single row of holes with a range of increasing size. There may be inter-connected surface lines or grooves which look like the impressions of rows of beads.

Below the surface, deeper down inside the pebble, the sponge creates a fairly hap-hazard network of spaces that resembles bubbles or an irregular sort of honeycomb. This inner damage is revealed when the outer surface of a badly sponge-infested pebble is either broken or worn away. " - Jessica Winder

 

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No doubt.

 

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

Thomas Mann

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Yes, interesting thought @abyssunder, your photo look like @salvo1989s's one.

theme-celtique.png.bbc4d5765974b5daba0607d157eecfed.png.7c09081f292875c94595c562a862958c.png

"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

photo-thumb-12286.jpg.878620deab804c0e4e53f3eab4625b4c.jpg

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