Thanks Karen. This is the only spot with staining in the kitchen. Call me crazy, but I may do marble again anyway and just find a spot for soapy dishes. :)

soap spill did irreparable damage to my previous granite counter

I bought a ledge type of sink and some accessories for it including a "grate". It fits over the top of my sink and I can use it to dry dishes; put wet stuff; gooky stuff or whatever else I might put on the counter. When not in use I put it on the bottom of the sink.

I also got a cutting board that can be used over the sink - so convenient to just swipe the stuff directly into the sink and if veggies and much less cleaning up the counter constantly or wiping it down.

I have a relatively small kitchen - it's a small urban galley kitchen but I opted for a 36" sink because I think having work space ABOVE the sink is more functional than more counter space for prep. I also got the little sponge caddy which will enable me to put the sponge or whatever out of sight and not on the counter.

Here's a picture of it when it was first installed but kitchen was still a work in progress. The ledge runs all around it and the accessories fit so they are flush with the counter.

How much of the porcelain sink is under that part of the counter? I ask because I wonder if the marble is leaching rust from the sink. It looks like a rust stain to me. The only area I have a tiny rust stain on my marble is near my sink. Porcelain sinks are often cast iron and will rust when in contact with bleach. That is why old claw foot rubs often have brown spots. If it is rust a peroxide poultice might help.

Call a fabricator now and have them come out to try to get some out. And then look into More 20 year sealer for your marble please.