I don't know if this porcelain tile looks at all like what you are seeking. I used one color for the bathroom floor. I loved it so much that I am using another color in the other bathroom. Apparently, they are durable and easy to work with. You'd have to see the tiles for yourself. If there is a Tileshop near you, they may have it on display.

Here is a link that might be useful: Supergres

I, too, fell in love with seagrass limestone. But after doing research I came to the conclusion that it would be a mistake to use it in the shower...so, I used seagrass on the counter top and tub surround but found a similarly colored porcelain tile for the shower and I couldn't be happier. I don't thing anyone would notice they are different, because the flow of the room just keeps it from jumping out as porcelain. However, I do have some other tile elements that distract from the differences in the seagrass and porcelain. I still love the seagrass more than any tile I have ever seen!

Here is a link to my bathroom and you can decide if it would work for you.

Here is a link that might be useful: seagrass and porcelain combo

Limestone, travertine, and other very porous open stones are for those who have OCD and don't mind hand scrubbing the dead skin cells and soap residue out of the stone's pores on a daily basis, or for those who can employ a maid to do do. Or for those who can mentally ignore the cleanliness state of the shower.

thanks, this pretty much confirmed what I have read elsewhere. We picked out a porcelain floor tile, it's a 18x18 rectified porcelain "Galaxy Bella". We are going to be tiling the master bath and bedroom with that (link below) The little fossil pieces in the Seagrass matches that tile perfectly. The Supergres Grigio would probably work, since the Desert Rose granite we are using on the vanity has that color grey in it. Oly, your bathroom is gorgeous, I'm going to play around with the idea of doing the tub surround with limestone as you did and maybe running a strip of it through the shower to tie the two together.

Here is a link that might be useful: Galaxy Bella

What about this?

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The tile on the lower right is Galaxy Bella, 18x18 through body porcelain, reticulated. That is what we are going to use on the floor regardless of what we decide on for the shower and tub surround.

Tile on upper left is one that I found today, it's Stonepeak Cesare Magnus Bronze Allure.That would go in the shower and tub surround instead of the limestone that we were thinking about before. It's reticulated 12x12 or 12x24 through body porcelain.