The good news is that it's in your bathroom not your kitchen.

Seal it and see what happens. At some point down the road you can replace it.

There some people who love the natural patina that comes with every day use.

Something similar happened to me. I ordered a vanity from Wayfair. Didn't read the description. The top was a natural marble type stone. My daughter put a bottle vinegar on it, she was using it a cleanser, it etched! There are ways to make a pumice and rub it out, but you only see it if you are looking for it.

Get a credit from the stone shop, apply to a quartz material.

Unless it has been cut? I doubt it's an issue.

You're not asking enough questions, doing enough due diligence for your project........or so it would seem.

Might want to post the plan and ALL the materials, before you end with other disappointments.

"I thought it was some marble looking material, but have learned it’s the real deal." : )

You can try a Stain-Proof Permanent Marble and Granite Sealer to see how that will work for you.

Get a credit from the stone shop, apply to a quartz material.

I'd try this route first. It only takes one slip-up with hair dye or the wrong cleaner, and your marble's shot ... much easier to put in something nicer and more user-friendly now.

IMO I think there is no way the store will give you a credit the vanity was bought with the top. As for staining we stay in a hotel in Rome the whole bathroom , floors, shower vanity are all cararra marble was installed a very long time ago. I still look s awesome . No matter what material you use for the top when dying hair it is best done not over the sink and if you must then cover the sink and counter . I think marble is so much nicer than fake plastic stone and a bit of common sense will be all you need. It is your master so no kids being silly .

Get a whole house filter and work at fixing your water--that is the real problem.

Marble can be restored by a stone restoration company. Some of our clients schedule them to come in every few years if needed. Just part of the maintenance, like occasional carpet cleaning or having wood floors restored. It's not "ruined".

I'm not sure if there is a difference between darker and lighter marbles but I had dark emporador marble in my last house on the floor, tub deck and vanities. It had a few etching marks but still looked great when we moved out 25 years later.

I would replace the top now. Lots of things in a bathroom that can stain it beyond hair dye. Like makeup. Oily things like moisturizers. Hand soap...

Ahhhhhh, I missed that .You bought a vanity that comes WITH the top. So how big is it? Sixty inches? Seventy two inches?

I'd look for a nice quartz remnant, and don't use the top. Why? When you stain it you will replace it, and have to call the plumber, get a quartz cut and template, RE INSTALL AND DO OVER.

You goofed. Fix it now. Another reason? Unless this vanity is totally free of side walls in your bath? It didn't come with side splashes. It probably has a back splash only. ....

And at the risk of repeating myself? Show the plan etc : ) for your bath as earlier stated, along with the rest of tile , etc in that bath.

FWIW we've had marble in our master for 12+ years and besides a bit of etching it still looks great - we do treat our water because I hate how all the bath fixtures become gross over time bc of hard water -not sure if that is a possibility? (I would want to protect a new construction bath no matter what vanity top I chose)

Get a water treatment system installed in your house.

Our master bath has honed calacatta gold marble, installed in 2010, so 13 years ago, and it still looks amazing. I am careful, but not obsessive. I did stop coloring my hair at home, and I use only products either made for marble for cleaning, or without dyes (shampoo, bodywash, etc.). There might be a couple of areas of etching, but if so, they are not noticeable. Our water is treated, so that might be relevant.

Our home has marble vanity top in guest bath, put in by prevous owners a few years ago. They obviously weren’t super careful, it shows lots of etching & a few stains. I paid to have a stone restoration company restore it, not a great result. I’m too OCD … going to replace it. If you’re careful with it I’d consider keeping it as is, I like the look & feel of it.

we have iron heavy well water

AFAIK, acids are the only way to remove rust stains.

Acid & marble are not good friends. Marble is quite porous; stains won't just sit on the surface.

Ounce of prevention: Don't install that marble top.

I put an onyx top on my vanity. That supposedly is worse than marble yet 5 years in, I still love it. Yes it's etched a bit, but otherwise it still is more beautiful than any manmade stone.