agatizid fossilized corals, sponge, something else?

[ivigo]

Hello.

Today i found in the same area close  to the beach in Greece 4 rocks.

Looks like agatized fossilized corals or sponge or something similar.

Maybe is only a strange rock.

This area in lost of time years have water very rich in silicon.

So, can anyone help for identification???

The rocks is very heavy.

I have a lot of photos but they need to put only one.

This one photo is a broken piece of the rock . It's little from outside and inside.

 

Thank you!!!

[ivigo]

One more photo from the other rock.

[Tidgy's Dad]

Looks like a calcite formation similar to boxwork to me. 

The interior could be a quartz mineral like agate that gives it the weight. 

[Rockwood]

I have a similar specimen that was identified as a sponge.

Mine was quite altered, and it's been some time since I've had it out though.  

[ivigo]

All the rock is silicon inside and outside.

It's two different rocks in photos.

One more photo from the first rock from inside.

[abyssunder]

If Greece, I wold agree with Adam. 

[ivigo]

10 hours ago, abyssunder said:

If Greece, I wold agree with Adam. 

I don't know who is Adam and yes , may be is some kind of sedimentary rock formation but is not soft like travertine or calcite . Is hard , scratch very easy the glass.

 

I think the rock now is silica , i don't know in the past. And for sure is from the sea.Maybe not coral or sponge but something similar (maybe other kind of plants).

[Coco]

Hi,

 

Adam is @Tidgy's Dad

 

Coco

[Rockwood]

Ah Ha. Found it !

my find IDed