what is this?

[Kristijan]

Hello

Yesterday I found this small, round, black, rock-like things on the beach. When I found the first one I thought it was some kind of stone (round and smooth - shaped by waves) but then I noticed it had tiny white dots all over it. Soon I discovered more of this things and they were all the same - round and black with many white dots. Only their size was different.
This one is ~10 millimeters in diameter,

and this one is ~8 millimeters in diameter

What makes me think it's some kind of living creature is this one:

It is only 5 millimeters in diameter and has light brown/pink color so it could be a "baby".

Does anyone have a clue what this might be?

Thank you

Kristijan

[biohazard]

At the moment I have no idea what those things might be (seeds? some crustaceans in their shells?), but could you be so brutal as to smash one and see what is inside? :)

[Kristijan]

Hi
I crashed one of them as you suggested. It was unbelievably hard. First I tried to break it with a stone but the stone cracked after a few hits so I had to use a hammer. Inside it looks the same as it looks from the outside (like black stone with little white dots) so it is definitely not alive (anymore). But because of their shape ( (almost) perfect circle when you see it from above and (almost) perfect elipse when you look at it from the sides) I am absolutely positive that they once were a living organisms. Now, after seeing what's inside, I would say that it must be some kind of fossil but I can't figure out anything else.

[JackBean]

What if it was stone shaped by water in the ocean or taken by some animal into gut?

[Kristijan]

What if it was stone shaped by water in the ocean or taken by some animal into gut?

I really don't think it's a stone. There are no stones that look like that on the beach and I've never seen anything similar anywhere else. Today I found more of them and now I have over 40 samples and they all look exactly the same (same shape, same color, they only differ in size which is 6-10 millimeters in diameter).

[Kristijan]

I examined the shattered sample once again more carefully and discovered something I haven't noticed before. It has a white/light gray "core" in the center and it's stratified so it looks like it has growth rings like the ones on the trees. It's clearly a sign that it was once alive and growing.
Unfortunately, I can't make a good photo of it right now but as soon as I get my hand on better equipment I will post it.

[vk4vfx]

Maybe immature coral polyps that have been polished up by the natural action of the waves? dunno but very interesting.

Stu

[Kristijan]

No one knows?

[Julie5]

How intriguing! Not sure what part of the world you are in, but if they are very small you could probably post them to some reputable natural history museum (hopefully they're not a bio-hazard)

Do post if you find out what they are.

(Maybe they are cetacean works of art??)(well, you never know how clever those dolphins are!)