A meta gem is a gem that only fits in a meta gem socket. A meta gem socket only accepts a meta gem.
Meta gem requirements[]
Prior to patch 7.0.3, each meta gem had a set of requirements. These requirements were that the wearer's equipment also had a particular number of other gems. If those requirements were met, the meta gem provided its bonus. If they were not, the meta gem was inactive.
Example:
For this meta gem, if the character's gear had
- -- at least 2 gems that "fit in blue sockets" (are blue, green, purple or prismatic)
- -- and 1 gem that "fits in red sockets" (is red, orange, purple, or prismatic)
this meta gem would be active.
A gem that matched more than one required color (purple or prismatic, for the above example) would satisfy any requirements that it matched. For instance, this meta gem would become active with as little as one blue gem and one purple gem socketed in equipped items.
A prismatic gem on your gear counted for all meta gem color requirements. One 
[Nightmare Tear], for example, was enough to activate your 
[Destructive Skyflare Diamond].
Meta gems added in Mists of Pandaria did not have this requirement.
What equipment has meta gem sockets?[]
Meta gem slots are sockets that (currently) only appear on particular varieties of headgear. Most often, meta gem slots are found on items intended for "end game usage": level 70/80/85/90 gear, arena gear, dungeon sets, and so on.
Meta gem properties[]
Meta gems of the same name adjective have the same effects, but may have different activation requirements.
| Prefix | Attributes |
|---|---|
| Austere | Stamina and Increased Armor |
| Beaming | Critical Strike Rating and Mana |
| Bracing | Intellect and Threat Reduction |
| Brutal | Melee Damage & Chance to Stun |
| Chaotic | Critical Strike & Increased Critical Effect |
| Destructive | Critical Strike & Spell Reflect |
| Effulgent | Stamina & Reduced damage taken from spells |
| Ember | Intellect & Increased Mana |
| Enigmatic | Critical Strike & Reduced Snare/Root Duration |
| Eternal | Dodge or Stamina & Block Value |
| Forlorn | Intellect & Reduced Silence Duration |
| Imbued | Intellect & Stun Resistance |
| Impassive | Critical Strike & Reduced Fear Duration |
| Insightful | Intellect & Chance to Restore Mana on Spellcast |
| Invigorating | Haste & Chance to Heal on Crits |
| Mystical | Chance to Increase Cast Speed |
| Persistent | Attack Power & Reduced Stun or Snare/Root Duration |
| Powerful | Stamina & Reduced Stun Duration |
| Relentless | Agility & Increased Critical Effect |
| Revitalizing | Versatility & Increased Critical Effect |
| Shielded | Stamina & Reduced Spell Damage Taken |
| Swift | Critical Strike & Minor Run Speed Increase |
| Tense | Critical Strike & Stun Resistance |
| Thundering | Chance to Increase Melee/Ranged Attack Speed |
| Trenchant | Intellect & Reduced Stun Duration |
Patch changes[]
Patch 7.0.3 (2016-07-19): No longer requires other gems to activate effect.
