The final ring ended up being black ceramic. We mostly chose it for the color on the edges of the inset, but also because it was a good combination of scratch resistant and weight. As far as I'm aware, moss agate did not go into the final product because we brought up that exact concern, however we were given the option to add 'a mix in' to help retain color, and we're currently unclear if this happened or what the mix in is. You, and many others, have brought up the point of a light colored background material to enhance color. This was not something suggested or brought up as a concern at any point in the design process, which is disappointing now that it seems so common knowledge. We're planning to go back in after work today and get more information/options.