Trying to make a compilation of gems to consider assuming a socket bonus is worthwhile. I know what gem you choose will change based on what stat you need but this is going to attempt to be a quick at a glance place to come in and get gem ideas. Below are the blue quality versions of the gems, but once epics are the standard the cut name will be the same anyways.

Note: As of now you may be forced to find "green" quality of the gems listed below until the rest of these gems are unlocked/put in game. Try and find the "perfect" cuts of these gems if the "blue" quality is not available.

Any input or feedback is appreciated, I will update this list if I miss something or picked a bad gem for a certain spec. I could definitely use some input on feral druid DPS gems.


Druid Gems:

Balance:
Blue:
- Purified (SP/Spi): Purified Twilight Opal - Item - World of Warcraft

Red:
- Runed(SP): Runed Scarlet Ruby - Item - World of Warcraft
- Veiled(SP/Hit): Veiled Monarch Topaz - Item - World of Warcraft
- Reckless (SP/Haste): Reckless Monarch Topaz - Item - World of Warcraft

Yellow:
- Rigid(Hit): Rigid Autumn's Glow - Item - World of Warcraft
- Quick(Haste): Quick Autumn's Glow - Item - World of Warcraft
- Veiled(SP/Hit): Veiled Monarch Topaz - Item - World of Warcraft
- Reckless (SP/Haste): Reckless Monarch Topaz - Item - World of Warcraft

Meta:
- Chaotic Skyflare(Crit/Crit damage): Chaotic Skyflare Diamond - Item - World of Warcraft


Feral(Tank):
Blue:
- Solid(Stam): Solid Sky Sapphire - Item - World of Warcraft
- Shifting(Agi.Stam): Shifting Twilight Opal - Item - World of Warcraft
- Guardian(Expertise/Stam): Guardian's Twilight Opal - Item - World of Warcraft
- Vivid(Hit/Stam): Vivid Forest Emerald - Item - World of Warcraft
- Enduring(def/stam): Enduring Forest Emerald - Item - World of Warcraft

Red:
- Delicate(Agi): Delicate Scarlet Ruby - Item - World of Warcraft
- Shifting(Agi/Stam): Shifting Twilight Opal - Item - World of Warcraft
- Guardian(Expertise/Stam): Guardian's Twilight Opal - Item - World of Warcraft
- Accurate(hit/exp): Accurate Monarch Topaz - Item - World of Warcraft

Yellow:
- Vivid(Hit/Stam): Vivid Forest Emerald - Item - World of Warcraft
- Rigid(Hit): Rigid Autumn's Glow - Item - World of Warcraft
- Accurate(hit/exp): Accurate Monarch Topaz - Item - World of Warcraft
- Enduring(def/stam): Enduring Forest Emerald - Item - World of Warcraft

Meta:
- Austere Earthsiege(Stam/Armor): Austere Earthsiege Diamond - Item - World of Warcraft


Feral(DPS):
Blue:

Red:
- Delicate(Agi): Delicate Scarlet Ruby - Item - World of Warcraft
- Fractured(ArP): Fractured Scarlet Ruby - Item - World of Warcraft
- Glinting(Agi/Hit): Glinting Monarch Topaz - Item - World of Warcraft
- Accurate(hit/exp): Accurate Monarch Topaz - Item - World of Warcraft


Yellow:
- Rigid(Hit): Rigid Autumn's Glow - Item - World of Warcraft
- Glinting(Agi/Hit): Glinting Monarch Topaz - Item - World of Warcraft
- Accurat(hit/exp): Accurate Monarch Topaz - Item - World of Warcraft

Meta:
- Relentless(Agi/Crit damage): Relentless Earthsiege Diamond - Item - World of Warcraft


Resto:
Blue:
- Purified (SP/Spi): Purified Twilight Opal - Item - World of Warcraft

Red:
- Runed(SP): Runed Scarlet Ruby - Item - World of Warcraft
- Reckless(SP/Haste): Reckless Monarch Topaz - Item - World of Warcraft

Yellow:
- Luminous(SP/Int): Luminous Monarch Topaz - Item - World of Warcraft
- Reckless(SP/Haste): Reckless Monarch Topaz - Item - World of Warcraft

Meta:
- Ember Skyflare(SP/Int): Ember Skyflare Diamond - Item - World of Warcraft
- Bracing (SP/Reduced Threat): Bracing Earthsiege Diamond - Item - World of Warcraft
- Insightful(Int/Mana Return): Insightful Earthsiege Diamond - Item - World of Warcraft

Resto should be:
(assuming socket bonus is worth gemming for, else go for Runed)
Blue: [Purified Twilight Opal]
Red: [Runed Scarlet Ruby]
Yellow: [Luminous Monarch Topaz]

Meta [Ember Skyflare Diamond]
(unless you really, really need the mana from Insightful)



No doubt if they ever make Crit or Haste scale better the gems might be worth considering but until that point... :P

Blue: Purified
Red: Runed
Yellow: Luminous

There's never any reason to gem for anything but Spellpower or Regen for Resto. Spirit now gives us some more SP, so Purified and Runed are the clear options for Blue/Red. If you have a Yellow socket, Luminous (Spellpower/Int) will give us more than Haste or Crit, due to the poor scaling we have with both of those stats.

For Meta, Ember is another option (+25 SP/+2% Int), though admittedly not as popular as Bracing or Insightful.

Edit: Wow, we all jumped on that fast. Delete this post if anyone feels its unnecessary.

As previously mentioned, using [Perfect Purified Shadow Crystal] is better than spellpower/stam for both resto and balance specs in blue slots.

For balance, it should only really be Runed (Red), Veiled (Red/Yellow), Rigid (Yellow) and Purified (Blue) as options I believe. Spellpower is better than haste generally, and you get more points per gem anyway (9 spell power instead of 8 haste on split gems, 19 spell power instead of 16 haste on pure).

You might want to add [Etched Monarch Topaz] to the feral druid gems.

Since the feral hitcap isn't that high it might happen that you are a bit over the hitcap but can't afford to lose a 16 Hit gem but you can afford to lose just 8 Hit rating, so you would gain 8 Strength by using this gem.

haste can still be considered on gems needing a yellow component (reckless only, never quick) once hit is capped. It is the best yellow gem stat for balance that doesn't cap.

The rounding errors on gems are worth considering as well. In TBC with blue gems, it was often better to use 2 reckless or veiled gems, than one runed and one great/quick, because you'd get an extra spellpower (10 vs. 9). With wrath blue gems, it's the opposite. Better to socket one runed and one rigid/quick (assuming you have a red slot and a yellow slot to fill where you care about the bonus) and get an extra spellpower over two orange gems.

Correct - Wowhead (obviously) does list them, so they must've been around on Beta. I am hopeful they'll arrive shortly (from dailies or what-not).

It might be worthwhile pointing out that a Perfect [...] Shadow Crystal will be missing only one stat point each (two in total) when compared to the rare gems, which makes them a reasonable replacement for the time being.

True, but there are very few yellow sockets in Balance gear (if any), and generally those that you do have will be filled with hit in order to just clip the cap (rather than getting more than needed). Point taken that haste is the more worthwhile option (over crit) if you happen to be hit capped and the socket bonus is worth getting.

[Royal Twilight Opal] in blue slots until [Purified Twilight Opal] is available.

Thanks for this, I've been looking for a clearly laid out list. Worth noting:

Insightful Eearthsiege (Meta) is a 5% chance for 600 mana. Someone with a pool of around 20k only gains 400, and only once, from Ember Skyflare, but the spellpower keeps it slightly appealing. Not sure where we'd need reduced threat, though - I'd tend to consider Insightful Earthsiege a DPS gem.

Resto yellow socket: Dazzling Forest Emerald Worth considering until Seer's Forest Emerald gets put in the game,
or Perfect Seer's Dark Jade if you demand actual Spirit instead of MP5.

Any idea if we're expecting the missing patterns in Ulduar? Or just a patch in general?

For Balance there are better options than SP/Stam for a blue socket slot. A [Perfect Purified Shadow Crystal] (As mentioned) or [Perfect Shining Dark Jade] (If you need hit) are your best options until the rare cuts are implemented.