GeologyRocks

I'm not sure.

I don't think it is an experimental rock. Artificial pebbles are used to measure longshore drift (how pebbles move on beaches) but they are typically different to the normal pebbles so that they can be found again and identified. For example aluminium or resin pebbles with a copper insert can be found with a metal detector or real pebbles of a non-native rock are used.

My best guess would be an eroded fragment of the base of a ceramic jar or bottle.

What is strange is that the embossing looks pretty fresh, but the pebble itself looks very worn indeed. I've seen some weird looking things on beaches - they all turn out to be rather mundane objects that have weathered in a strange way. The weirdest was a ball of barbed wire, about a metre in diameter, that was "welded" solid. If it wasn't for the few distinct "barbs", it would've looked like a ball of solid steel!!

Bizarre!

I'm thinking it was orignally a kind of clay because the stamp, as mentioned, looks like a date stamp where the numbers are manually turned. A pliable material would be required to make the stamp work and then I assume it would be fired.

However, if it was clay-based then it should be scratched by a screwdriver and not the other way around - unless the material gives a silvery metallic streak? Have you tried scratching with some glass (beer/wine bottle)? NOTE: Health warning - be careful of broken glass. I don't want to find myself being sued!

My other thought is maybe it's a fragment of a larger object when has been broken and weathered into it's present shape but if that was the case why do the numbers look so fresh?

A very intriguing mystery. You say you're from Hampshire, maybe you could try making contact with Southampton Uni? They have a good oceanography department, not sure about their Earth Science/Geology side. If you do find out what it is I'd love to know.

My thoughts on this, sorry not in any particuar order so might seem a bit haphazard:

Firstly how heavy is the rock? Is it possible that it is weathered iron or some such metal? The dark circular band on the front/back looks like corroded metal to me.

Secondly the date stamp looks like it has been made from individual dies, more like a typewriter than a date stamp, as the individual numbers are different heights.

My guess would be that it is the sheared head of a very weathered ship rivet of some description:

Maybe a putty sealant of some kind, On an ofshore craft. A two part mix like an epoxy resin then formed over the number maybe on a engine or something, then left to cure. Then it found its way into the sea and ended up in your hands. Maybe it never done its job and the craft ended up on the sea floor? just an idea/nice story!

I do like the idea for a story but if it was a sealant over some numbers it would effectively be a mould and wouldn't the numbers in the 'rock' therefore be a mirror image rather than reading the correct way around?

yeah you're right about that al.  Also, chances are whatever it would have gotten the  numbers off of would have a smooth surface for the serial number, not up and down like this.  Plus if you notice the peaks and valleys in the rock, the numbers follow those, which would lead me to believe that they were put onto that rock specifically, perhaps by either a collector or seller.

Furthermore, if you look at the dark ring on the other side of the rock it has what look like small clasts within it, which are white.  This leads me to believe that part is rock, but the two different colored materials inside confuse me.  Maybe some kind of concretion that was eroded from its host rock and got buried and subsequently lithified within that sediment?  I don't know.

Still don't think it's rock.

Probably ceramic. Erosion of thin layers of different materials gives concentric pattern. Not natural.

Throw it back in the ocean.

Fascinating. It looks as though the numbers were made using number punches that are used for puting id numbers on metal objects but of course this could not be done in stone. There are very few soft, plastic, materials that would hold such a clear imprint. The marks above the numbers are telling us something but I don't know what yet. Put the number 299537 into Google and you get about 15,000 hits - there may be a clue there somewhere.

Now, the reverse side. The circular recess is not complely filled with the insert. Is the dark stuff possibly a 'glue' of some sort? Does it look as though it may be bonding the inner disk in? If so then it would appear that the main part was made to be bonded to something else which has been broken away.

Is it possible that the 3 (possibly 4) indentations on the rim are made by someone holding it while it was soft?

Getting an accurate figure for its density might help but you'd have to break a piece off to do that as it's more than one material. If you did, you might find it in look-up tables.

Is it soft inside? Is it squashable? does it 'ring' like metal when struck? Does it sound hollow?

Oh, go on, take it to the university or the museum.

Ben

hi

i found a stone on southsea beach in hampshire today!

its the same colour as yours is round and has the number

186707 on one side and three round indents on the other

looks kinda like a paw print would...

what is it!??

do you have a photo of it?

Found one of these yesterday at Lepe (near Calshot). The number is 266050. Feels slightly metallic but not magnetic as far as I can tell (the very technical method of holding a magnet to it ) which sort of rules out iron and steel rivets.

Ok, that's three now all found in a localised area. Has anyone found one of these from a beach which isn't in Hampshire? Preferably one that's not on the South Coast.

What I'm now thinking is that they could be part of some grand experiment (probably from Southampton Oceanography Centre)  to track sediment movement of coarse gravel/cobble sized particles. However, the fact that there seem to be over 250,000 samples (assuming the numbering is sequential) means there has to be some method of remote tracking which is cheap, robust and long lived. That's where my theory falls down, I can't come up with a cheap method that would allow these pebbles to be tracked easily - I'm thinking small radio transmitters would be far too expensive. In fact, just manufacturing the pebbles would probably be too expensive for a research project, unless it has some grand aim along the lines of tidal/current power generation.

Any other ideas?

Tracking could be done with metal detectors if they contain some metal - walk along beaches on the south coast, with the detector and see what you find....Very cheap (assuming you get students to do the work )

Except the pebbles would need some specific signal or the detectors would pick up every piece of metal they come across.

I suppose the simple answer would be to ring Southampton Oceanography and ask - but that'd take all the fun out of this wild speculation!

I have t6o agree with Benauld that does look very alike. as he/she said it depends on the weight.

What a conundrum you've started, Steve. And no resolution yet?

They definately look like some numbered marker that was affixed to something for some reason. Almost like in someones collection. The first two are very similar, but the third looks molded and the numbers are in relief instead of impressed. The third specimen may be older than the other two,(you know how budgets get cut back).

I am assuming they are all related to the same purpose since thay were all found in the same area and if you haven't found an answer yet I would check with your local archaeology department. They have probably come across these things before.

And please let us know what you find out. It may be related to geology in some way afterall.

Thanks,  Joe

http://naturenet.net/blogs/index.php/2008/04/18/codling

Found this while browsing images of pebbles.  Sounds like fun and I wish I had one. Must go and have a root around.

Fran

Wonderful! Thanks for posting that. It had me scratching my head for a while.

And there we were trying to find a logical function for them - that's where we went wrong, IT'S ART DARHLING!!

It would have been nice if he had kept a database of the numbers and a little info on who/where/when they were created but hey its art not science!