We are guessing without elevations or photos showing the space as well as your selections. Generally the trend is toward one backsplash material but there are certainly times where an accent works, hard to know about your situation.

Of course, we don’t know anything about your kitchen until you share more information …but here’s what I did in my basement ADU about two years ago, in case it’s helpful. I had a vision before we began construction, and I still love it-although I agree it’s no longer a trend-and wasn’t then, either. I did not choose to “frame” it; for the non-accent backsplash I used a subway tile (Adex) and wall color that matched the background color of the geometric tile (Pratt and Larson).

Thanks for sharing your photo. Looks like you went end to end so I assume the tile thickness was similar. i have not picked out tile yet but was thinking of this concept

Thanks Cat! And now, looking at the photo, I remember that although the geometric tile was not “framed”, we did use a thin pencil liner (I think that’s what it was called) along each vertical side. The thickness of the tiles was close enough to work.

I like the look of @chinacatpeekin ADU. I agree a thin pencil liner was used to sort of frame out the accent tile. If you magnify the picture you can see it.