Like you, I am not really a great fan of jewels made from coloured stones only. I think that the beauty of coloured stones is much more enhanced when it is set within a diamond surround.
Yet, I was amazed at the size and the deep intense colour of the emeralds in Queen Sofia's necklace. These are probably very valuable stones!
I think Queen Sofia's dark shiny dress did not do justice to this emerald necklace. A pale dress would have been much better - as well as an emerald brooch.
Regarding a good setting for a necklace of round cabochon emeralds, I think interspersing the emeralds with pearls (as in the emerald and pearl necklace presented by Queen Mary to her daughter-in-law Alice, Duchess of Gloucester, as a wedding gift) could be a good option: