A fossil of a bivalve or just a rock? Found on Croatian coast.

[MS3]

Hello,

I found this on a beach along Croatian coast and was unlike any of the surrounding rocks/geology.  It's symmetrical and submarine-shaped.  I'm wondering if it's a fossil v. a natural formation.  Any information is greatly appreciated!

[FranzBernhard]

Does not look like a fossil.

Looks like a banded rock with a veinlet running through it.

Franz Bernhard

[supertramp]

not a fossil, as FranzBernhard says;

especially in the third pic, it reminds me of a superficial pattern which I’ve seen occuring on microfractured limestone stream pebbles

http://www.naturamediterraneo.com/forum/topic.asp?TOPIC_ID=198324&SearchTerms=calcilutiti

ciao

[MS3]

Thank you for the input and a very helpful link!

[debivort]

I agree with FranzBernhard and supertramp, but it's an intriguing rock, and I would definitely have thought it a bivalve at first glance.

[Lousde]

I agréé it's a rock, no fossil hère, sorry.