Keep it . It looks great and it's something unique !

I agree, keep it. It looks beautiful. My one question is, are the stairs slippery so they would be unsafe?

If they're not slippery, keeping them will probably be best. Once you start messing with stairs you run into all sorts of code issues so it's best not to touch them unless you have a good sized budget.

You could probably cover them in a solid color solid surface in 1/4" thickness, but that may take you out of code compliance. Think reversability, please.

Beautiful. Different. Stunning.

Your marble with that fantastic coloration and those striations is mined out. We’re left with Ming Green marble instead if someone wants light green marble. Analogous to wanting Patrick Swayze, and getting his brother Don Swayze instead. You have something amazing. Make your other decor choices to work with it.

You might also think about hiring a marble restoration company to buff it, and remove what might be imbedded dirt and stains; it might look more brilliant. But only do that with a top-notch company very experienced with marble. No low-priced “flooring companies” which will apply weird treatments to it, and ruin it. If you don’t have a really good marble restoration company in your area, then just leave it alone.

My one question is, are the stairs slippery so they would be unsafe?

I can't be the only person thinking of the stairs that led to Finny's death in John Knowles' novel A Separate Peace.

Those stairs are absolutely beautiful and changing them would be tragic. And green stone is in style.

I would give a kidney to have that staircase. I'm so glad you're keeping it!