I wouldn’t do the Greek key mirror but a really big mirror with a wide gold frame would be lovely. Is your chandelier gold?? Hard to tell in the pic,

https://www.homeclick.com/lighting/14-460-631-0-688173/Quoizel-Lighting_Division---Four-Light-Pendant-DSN2824EK.htm

Gold in the center with black hexagon

Are you guys not a fan of mirror in dining room? Just thought it would add dimension to the room. Would art be better?

I'm a fan of art anywhere you can find a place to hang it. Mirrors should always double/reflect something beautiful or interesting. I think they can be a distraction in the dining room; especially if you have vain friends over to dinner!

I would keep the mirror as minimum on details as possible. Your lamps and your chandelier already have a lot of edges to them. I also would not do gold since your lamps are gold their details will just disappear against a gold mirror. If you were to do a mirror I would do a mirrored framed mirror. So basically all mirror. I think you might be selling the room short by not bringing in a large great piece of art that plays to your homes color story. It will show better against you dark walls.

I agree with the others. If you go with a mirror, keep the frame simple so your room doesn't look over decorated. Your room has very little colour, it's all neutrals and very brown. I would love to see colourful art on that wall. Choose art that speaks to you and you absolutely love.

Actually, I’m not that crazy about the lamps with that chandelier either.

What style do you recommend? Or would you do away with lamps

I think we need to see more of the overall room. I’m just going by what little I can make out . There seems to be an ornate table which imo creates a disconnect in style with the chandelier. I would be hard to suggest a mirror but based on the chandelier alone I would say keep it simple. Looking at what I think the table looks like then I would say go ornate but it’s the chandelier that will be the main focus there! As there are what appears to be other angular pieces in the room I like these softer lamps. Also for the light color against the dark wall for drama. If you don’t want traditional lamps these torchieres are another idea.