Found this on a website wwwcannotlinkto3000.com/death-knight/guide-to-wotlk-jewelcrafting-designs.html-seems safe enough, but I cut and pasted in case its a sketchy sight.
These are gem designs that drop from boss mobs or normal mobs. The rate is 100% as long as there is a JC in your party who can learn it.
Red
Fractured ( +16 Armor Pen. ) - Nascent Val'kyr mobs, Storm Peaks
Precise (+16 Exp ) - Herald Volazj, Heroic Ahn'kahet
Orange
Accurate ( +8 Hit, +8 Exp ) - Ironwool/Plains/Stoic Mammoth, Storm Peaks; Shattertusk Mammoth, Sholazar Basin
Deadly (+8 Crit, +8 Agi ) - Keristrasza, Heroic Nexus
Deft ( +8 Agi, +8 Haste ) - Sjonnir the Ironshaper, Heroic Halls of Stone
Fierce ( +8 Str, +8 Haste ) - Ingvar the Plunderer, Heroic Utgarde Keep
Yellow
Thick ( +16 Def ) - Cyanigosa, Heroic Violet Hold
Green
Radiant ( +8 Crit, +10 Spell Pen. ) - Frostfeather Screecher/Frostfeather Witch, Storm Peaks
Timeless (+8 Int, +12 Stam ) - Prophet Taron'ja, Drak'tharon Keep
Blue
Purple
Defender's ( +8 Parry, +12 Stam ) - Stormforged Ambusher/Champion/Artificer/Infiltrator, Storm Peaks
Infused ( +16 AP, +3 mp5 ) - Anub'arak, Heroic Azjol'Nerub
Meta
Austere Earthsiege ( +32 Stam, +2% Armor from Items ) - King Ymiron, Utgarde Pinnacle
Bracing Earthsiege (+25 SP, -2% Threat ) - Eregos' Chest, Oculus
Eternal Earthsiege ( +21 Def, +5% SBV ) - Loken, Halls of Lightning