I have a shallow yellow stone to set in a new mounting. How would you set this stone to enhance the color and sparkle since it’s lacking the point in the bottom so there’s fewer facets?
definitely yellow gold! is this a portrait cut? or does the lighting just make it look that way? if it's a portrait cut, I would worry that you'd see the cup through the stone.
Look at some antique settings with rose cuts for ideas. You may want to consider a closed back or cup setting with some access for cleaning. Looks like a portrait cut stone with maybe a little more faceting on the edges than you sometimes find.