IMO you do this space in the same red oak as the rest . I would not do a different fllor and for sure no fake wood next to real. Why marble? What kind of marble look?

I do not want real wood in this room as I would like a pet friendly/child friendly surface. All hardwood floors in the home are being refinished. This is the only large room in the house without hardwood. Some of the new luxury vinyl flooring looks like marble, with a matte finish. I wanted something lighter, rather than darker so that the room looks brighter year round.

Marble look would be cringe. You will have to physically address the lighting to make a dark room be light. Light surfaces just look dark and dreary in dim light. You will also have to remove the existing floor, and address the subfloor prep, to lay any new flooring. For flooring choices, look at something that looks like encaustic maybe, or a fabric look that isn't really look specific. Daltile Bellant would be a good choice.

https://www.daltile.com/products/Concrete-Look/Bellant

Yes, it is limestone and midwest. I agree with others, that having the same flooring as the rest of the house would be best, the same red oak, but I was really looking for a little different look. Not crazy about the grey luxury vinyl which is very popular in new homes etc. Just looking for something different and with the hundreds of choices, it is so hard to visualize them. The best bet in the end might just be the same hardwood as everywhere else.

The current flooring has been removed and the subfloor is fine. I am having the floor, whatever it ends up being, professionally installed. The chairs in the pic do not belong. I took this picture before the furniture left in the house was removed.

Can you take a picture with your back to the fireplace so we can see how this room relates to the rest of the house?

This "buttermilk beige" limestone look tile has some gray and tan in it that should work with the adjacent flooring.

And the pattern isn't as busy as a marble look or an encaustic tile.

Definitely get samples to look at in your space and in your light.

https://www.homedepot.com/p/Lifeproof-Buttermilk-Beige-6-MIL-x-12-in-W-x-24-in-L-Click-Lock-Waterproof-Vinyl-Tile-Flooring-23-8-sqft-case-I796106L/311343433

I opted for LVT in my home because it was the right choice for my lifestyle.

I originally wanted a very light LVT, but learned about "Environmental Staining".

The flooring stores assured me that there are not issues with yellowing of LVT like there used to be and discoloration, if it occurred would be covered by warrantee. Being the distrustful type, I called the manufacturer and asked specifically about yellow staining in traffic areas caused by residue on our shoes after walking across the blacktop driveway.

It is not covered by the warrantee and is specifically excluded in the "Environmental Staining" clause.

I had a fading issue with a Metroflor LVT installed 15 years ago. It did fade in front of south facing sliders. A rep came out and said it looked good until I threw a scrap from install on the floor. He asked what is that, I told him, and got a new floor on them! They initially tried to tell me the blacktop drive thing but we have concrete.

I'm not sure the replacement hasn't faded also.

Does it still does this or has this been fixed with time?

Since you don't want oak, I would suggest a tile, with a pattern that doesn't mimic wood, marble or encaustic. Something stone-like in a neutral beige - in that very neutral room, even a hint of color (except pink, as too many beige or cream tiles tend to have!) Large tiles if you can find them, as well.

Deegw's suggestion I like for pattern and color.