Hello,
I would like to suggest for mottled gems elemental gems, that if you put them into a weapon. They do not just increase the elemental damage by 10%, but also add the infusion as well. As it stands now, their use in weapons is quite limited. If you add them into a weapon that has their element, they “only” remove the natural damage penalty. For their full use you need to find weapons that come with the element without gem or Facet