That's limestone, I think. It's always hard to tell without actually seeing it, but that's what it looks like to me. The slightly wavy layers are caused by bioturbation, which is when seafloor critters disturb the naturally flat-lying layers. It's a cool rock with a lot of stories to tell!

My first thought was limestone, look at vein cut silver Travertine.

@chispa - I was thinking silver travertine as well. I am pretty sure that’s what that is.

Is there a “what is this stone” thread? I’ve got one I’m not sure what it is. It’s labeled white soapstone. It is called by the counter guy a marble. And similar things online range from marble to quartzite. I’m not too worried about labels or etching and appreciate the patinas that natural stones can get. But I would still like to know what it is.

@karin_mt: Totally hijacking here, but Karin do you know definitively what Costa Esmeralda is? It's always sold as granite, but my fabricator said it's quartzite because it's so blasted hard. No trouble with it and I love it regardless of what is it -- just asking out of sheer curiosity.

Costa Esmeralda is quartz-rich, for sure. It's closer to quartzite than any other commercial stone type, but geologically speaking I don't think it's technically quartzite. I think CE is an igneous rock, while quartzite is metamorphic. I have a piece in the basement - I should go look at it again.

Still a bit of a mystery then. Eh, whatever it is it sure is beautiful!