Currently only PvP gems and Unstable Topaz are categorized as "unique". However, Heroic gems, which are also unique, are not marked as such, allowing the users to use more than one heroic gem in their gear.
There is also no option currently to add a "custom" gem (e.g. a 4sp/4int healing gem) or to add a meta gem slot to a custom item (e.g. Exorcist's Silk Hood)
Currently only PvP gems and Unstable Topaz are categorized as "unique". However, Heroic gems, which are also unique, are not marked as such, allowing the users to use more than one heroic gem in their gear.
The heroic gems are:
Infused Fire Opal (30551) Shining Fire Opal (30564) Potent Fire Opal (30588) Fluorescent Tanzanite (30600) Glowing Tanzanite (30555) Seer's Chrysoprase (30586) Lambent Chrysoprase (30606) Rune Covered Chrysoprase (30560) Dazzling Chrysoprase (30589)
There is also no option currently to add a "custom" gem (e.g. a 4sp/4int healing gem) or to add a meta gem slot to a custom item (e.g. Exorcist's Silk Hood)