Rather then have 3 pieces of jewelry that, in their current form, aren't as desireable as personally crafted ones, there should be jewel sets that can be placed in the necklace, shield, helm, weapons and claw slots. This way people won't have remove 3 pieces of much liked jewelry (etc.) and instead just one, if that, if they already have them socketed.
For bipeds they could wear 3 different sets, weapon, armor and jewelry set. Dragons could wear them in claw slots and chest scale (I think that is the right scale for socketing) and the dragon jewels could be slightly more potent to make up for only having two sets rather then the 3 possible for bipeds.
Lastly any effects they could have could all be stackable with now existing crystal effects.