What I'm wondering is this - is there any hand soap that someone has tested and left on marble (accidentally or on purpose) that hasn't etched marble? I know the Softsoap I use currently will etch a sample.

I see a lot of recommendations for pH balanced but hard to determine which ones have that.

There's a Martha Stewart product on Amazon that says it's marble-safe. And I've seen EO products recommended but it doesn't seem to say anything about being marble-safe on their website.

I want to order something soon so we have it when we move in.

I was using Kiss My Face Foaming Hand Soap when I could find it at my local Whole Foods store. I never saw any etching or stains, though periodically I think I found soap residue on the counter. I picked this soap because the back of the bottle said "pH neutral" at some point. Unfortunately, I have not been able to find this soap at Whole Foods for several months. So I've been using Kiss My Face Moisture Hand Soap. In this case, there have definitely been blobs of soap left on the counter for some time. I seem to be the only one in the house capable of recognizing blobs of soap on the counter and cleaning them up. (Sorry for the brief rant.) I haven't noticed any etching, though I've noticed dark spots that remain after scrubbing with water and stone cleaner. I think they might fade over some time as one that I found a few weeks ago seems to be gone (and replaced by new dark spots). So I think the soap is safe, but I am not positive. I think the "moisturizing" ingredients (maybe the olive oil?) might be settling in the marble for longer than water does and darkening the stone. So far I haven't seen any etching at all on the stone, though it's really only been used for washing of hands or hand washing delicate laundry.