Stranger, I have Caesarstone Smoky Ash which seems nearly identical to Charcoal/Zulu. It has a little taupe, but no pink (thank goodness). Its price was comparable to granite. I was looking for something dark gray without a lot of movement, so this fits the bill. Not sure I would choose it again, but that's academic at this point. My cabinets are white and my floor is red oak. I decided I wanted something more yellow/gold for my backsplash and the good people here at GW talked me out of it. I'm instead going with a cream crackle subway. Although I'm not convinced my first choice was totally wrong, I think a more neutral b/s is going to work better in the long run. It doesn't fight with my counter. I'm not having any special accent tiles or liners. I was surprised how expensive tile setters are and non-field tiles, like bullnose. I'm grateful I had just enough left in my budget to cover the b/s. Many here will suggest you just hang tough and wait a while until everything else is done. I tend to agree with that. Get LOTS of tile samples.

With the red pendants and modern hardware, it looks like your style 'wants' mosaics. I think a mosaic would look great! I think you can do something bold on the b/s -- everything else is neutral, except for the pendants. I don't think it would look too masculine. Maybe use a more muted colour for the b/s to 'feminize' it a bit if you are concerned about it. On the other hand: I love the subways posted by kitchenaddict. However, I think the red pendants would look out-of-place with the subways. I don't know...what do you think? It just seems like mosaics would be a more natural fit in this kitchen.

If your choice were only between to 2 you originally posted, I'd choose the one on the right--the cream one. From the photos it looks like it works very well with your quartzite. The gray one is "off" just enough not to look pleasing. However, as many have noted, either one is more difficult to clean than a smooth surface. What sort of cook are you--very neat or more devil-may-care? If you are very neat and do not splash much when you cook, then you may get away with the split-faced marble, but if you are a more exuberant cook, you may find it a challenge to clean. The mother of pearl is very formal and quite busy, so it's going to compete with the counter tops as well. Personally, I would use a smooth crackle tile in a tan/beige tone to work with your quartzite. Simple is always good.

Have you thought about stainless steel backsplash tiles? https://www.houzz.com/products/4x11-honeycomb-matted-metal-peel-and-stick-backsplash-tile-set-of-3-brushed-st-prvw-vr~100903589. These tiles would look great with your stainless steel appliances.