What caused the stain?

I was mixing cocktails with lime juice(I know), but had a cutting board and dishcloth over the area.
later, the stain was there. must have soaked in the dishcloth or possible there was a stain on the cutting board b/c the stain is a perfect rectangle about 5 x7" yellow ish

Call the dealer where you bought your marble.

I've heard that either Hydrogen Peroxide, Baking Soda or scouring powder with bleach can work, but unless you're willing to experiment (with a tiny amount of each), a professional stone restoration company will be your safest bet. (Your installer *may* know, but a restoration company will definitely know) Please let us know what does work for you once you've solved this.

Thanks!
Steve

FWIW Oxyclean IS peroxide and soda. Marble is different than granite because marble has a lot more calcium. Be sure anything you try is designed for marble and not granite.

Hi bmiller,
I'm just checking in to see what happened with your marble counter. Did you have any success working on the stain? I came across this ideabook today and thought of your question. i'm not sure it has anything in it you don't already know, but it might:
https://www.houzz.com/magazine/using-white-marble-hot-debate-over-a-classic-beauty-stsetivw-vs~513903

installer came out on Monday and sanded but it did not lift the stain. someone on Houzz suggested contacting a stone restoration specialist and I am looking up reputable ones in the area. thanks for your info. i will look at it. I will keep houzz friends informed if I come across a satisfactory result.

I'm so sorry it hasn't been fixed yet. I'll keep fingers crossed that you find a solution.

Hi BMiller, I'd suggested the stone restoration company previously because I've found that they are much more experienced in dealing with this problem than fabricators/installers are. I hope it works out well for you! Please let us know how it goes.

Thanks

Steve

I found something called Bar keepers friend which is a cleaner. It is wonderfu.

Have Your used vinegar and water?