Can rust stain around the drain of a marble sink top be removed?

You can try a poultice of flour, or baking soda. You can also see if it can be polished out. Don't know if CLR will damage the marble or etch it,

yes. Use vinegar let it sit overnight and then wipe it off in the morning

Iron Out. Fabulous product for rust removal.

Maybe. A paste of baking soda and hydrogen peroxide can often remove rust. Dry the sink, smear the paste on the stain and let it sit at least ten minutes. Then scrub with a sponge. If that removed some stain but not all, repeat. Best wishes 😇

"Rust stains are common around faucets due to particles of iron in tap water. The chlorine in tap water can cause these stains to become even darker. Marble is a porous stone, which allows stains to soak into it more easily and requires a poultice to remove the stains." Read more : http://www.howtocleanstuff.net/how-to-remove-rust-stains-from-marble/

PS Iron Out is available for sale at WalMart in different sizes and forms (liquid, powder, etc) for just over $5-$12. Good luck!