The island counter top doesn't look white in the image. Is it really white or an off white or even beige? Is it a natural stone or is a solid surface composite such as Sile stone?

Your granite is very dark, floors and cabinets mid tones, so lighten with off white subway tile. Make sure not to do white as it will not be the right undertone.
Also, is there a way to remove those curved pieces above the cabinets with lights in them?

The two different countertop surfaces were not a great choice. As you've installed a SS vent hood why not consider updating the black appliances too? I'm inclined to source a copper colored backsplash tile (1 color not mosaic or any pattern) Best of luck.

How about a mosaic like this?

Sorry, it's way too busy and dark and will compete with the granite. You need much lighter and solid color. Make your counter the star.

I wouldn't have used two diff colors for the counters but we just bought this house and the previous owners had it this way. Its too costly to replace all the counters so will need to work with it. Thank you for your suggestions.

Kea Interiors ~ I am afraid that would be too bold, I am not sure if black will work, this room does have allot of windows on the other side.

Rusty Empire ~ Yes, the eventual plan to replace those to steel appliance. I like your idea of copper colored tile, thanks!

Debra Toney, AIA Assoc. ~ It is white stone, I'm not sure what type it is. Yes, the picture doesn't show it well.

My granite is similar to your dark granite and I have beige 4" square tile as a backsplash, which blends with my wall color.

gilgo ~ will look into that, thanks!

I think going with a mosaic that can marry the two different counter tops would be best. It will look intentional. Introducing a third type of stone/material could come across as mismatched and uncoordinating.

I'd go with a beige, cream or steel mosaic with just variations/shades of one color not combinations of color.

I think the mosaic pic from previous suggestion looks great

I like the idea of mixing the three, will check if I can find something on houzz. Thank you so much!

Thought about it some more. Another thing you can do is to put a plain penny tile that is a color match to the island counter.

thanks! will try and get hold of samples to see how it looks.