Today I'm looking at crafted gems. This discussion doesn't consider the gems that can be purchased, are quest rewards or are drops in dungeons.
When you look at the gem possibilities for socketing you gear, you quickly can determine the following about the primary colors of gems:
- Red Gems affect Strength, Attack Power, Agility, Spell Damage, Dodge or Healing
- Blue Gems affect Mana per 5, Stamina, Spirit or Spell Penetration
- Yellow Gems affect Spell Critical Rating, Spell Hit Rating, Intellect, Resilence, Spell Haste, Hit Rating, Critical Rating or Defense.
So, that leaves us with 5 combinable red characteristics, 3 combinable blue characteristics and all 8 yellow. So there are a potential for 15 purple gems (of which there are 6), 40 orange gems (of which there are 7), and 24 green gems (of which there are 6).
Sadly, its obvious that Blizzard can't put every combination into the game. Some of the combinations wouldn't even make sense for any class in the game (Spell Haste & Agility or Spell Damage & Hit Rating), but some of them would be welcome additions (Attack Power & Hit Rating or Healing & Spirit).
Please visit the gem resource I mentioned a few days ago to determine exactly which gems you want in YOUR gear.
Edited: There is indeed a crafted gem that combines healing and spirit , and not surprisingly is purple. However, it's pretty well hidden in that the base gem requirement is not a Shadow Draenite, Nightseye or Shadowsong Amethyst. Instead, the base gem is a shadow pearl. Thanks to Awlbiste's eagle eyes for catching this mistake.