Gem Quality Bonus Compendium

Since I haven't seen a thread that covers the updated bonuses granted by GCP to gems I'll start this one and hopefully, with the help of fellow forum-writers, obtain a full list.
The value after the column represents the bonus granted by 1% quality.

{DISCLAIMER}: Some of this data may be outdated, as the partial source is several months old and some data was insufficient. If you find an error or have some information that I missed, please post with your correction.

Portal: +2% Cast speed

RED SKILL GEMS

Anger: +0.5% AoE radius
Cleave: +1% Attack speed
Decoy Totem: +2% Totem life
Determination: +0.5% AoE radius
Dominating Blow: +0.2s Duration
Enduring Cry: +1% AoE radius
Glacial Hammer: +1% Increased Freeze duration; +2% Increased Chill duration
Ground Slam: +1% Increased stun duration
Heavy Strike: +0.5% Attack Speed
Immortal Call: +0.05s Duration per Endurance Charge
Infernal Blow: +1% AoE radius
Leap Slam: +1% Increased stun duration
Lightning Strike: +2% Chance to pierce
Molten Shell: +1% Chance to Ignite
Rejuvenation Totem: +2% Totem life
Shield Charge: +1% Increased physical damage
Shockwave Totem: +2% Totem Health
Sweep: +2% Increased knockback distance
Vitality: +0.5% AoE radius
Warlord's Mark: +1% Chance to grant Endurance

RED SUPPORT GEMS

Added Fire Damage: ???
Blood Magic: +0.5% Attack speed on Low Life
Cold to Fire: +0.7% Cold Damage; +0.7% Fire Damage
Knockback: +2% Knockback distance
Iron Grip:+0.5% Projectile Damage
Iron Will: +0.5% Spell damage
Life Gained on Hit: +0.35 Life gained for each enemy hit
Life Leech: +1% Increased life leech rate
Melee Damage on Full Life: +0.5% More physical damage on full life
Melee Physical Damage: +0.2% Melee Physical Damage (Need more comparison info)
Reduced Mana Cost: ???
Stun: 0.666 Reduced stun threshold
Totem: +1% Totem duration

BLUE SKILL GEMS

Clarity: +0.5% AoE radius
Cold Snap: +1% Increased chill duration; +0.5% Increased freeze duration
Critical Weakness: 1% = +1% Extra Critical Strike Damage taken
Discharge: +1% AoE radius
Discipline: +0.5% AoE radius
Elemental Weakness: -0.35% Elemental Resistance
Enfeeble: 1% Reduced accuracy rating
Fireball: +1% Chance to Ignite
Firestorm: 0.2s Reduced fireball interval
Freezing Pulse: +2% Projectile speed
Frost Wall: +0.5 (units) Wall length
Ice Nova: +1% AoE radius
Ice Spear: +2% Projectiles Speed
Lightning Warp: +1% Cast Speed
Power Siphon: +0.5% Increased damage
Purity: +0.5% AoE radius
Raise Spectre: +1% Increased minion move speed
Raise Zombie: +0.5% Maximum Life; +1% Minion move speed
Righteous Fire: +0.5% Spell damage
Shock Nova: +1% Chance to shock; +2% Shock duration
Spark: +2% Projectile Speed
Summon Skeletons: +1% Minion damage
Tempest Shield: +0.5% Lightning damage
Vulnerability: +0.35% Physical damage
Wrath: +0.5% AoE increase

BLUE SUPPORT GEMS

Added Chaos Damage: +0.5% Chaos damage
Added Lightning Damage: +1% Shock duration on enemies
Chance to Ignite: +1% Ignite duration
Concentrated Effect: 0.5% Reduced mana cost
Elemental Proliferation: +0.5% Chill, Shock, Freeze and Ignite duration
Faster Casting: +0.35% Cast speed
Increased Area of Effect: +0.35% AoE radius
Item Rarity: +0.35% Increased Rarity
Minion Damage: +1% Minion damage
Minion Life: +1% Minion Life
Remote Mine: +0.35% Damage

GREEN SKILL GEMS

Bear Trap: +1% Physical Damage
Blood Rage: +1% Attack speed on low life
Conversion Trap: +0.5% Skill effect duration
Detonate Dead: +2% Casting Speed
Double Strike: +0.5% Attack Speed
Dual Strike: +3% Critical strike chance
Elemental Hit: +0.35% Critical strike chance
Ethereal Knives: +1% Projectile damage
Explosive Arrow: +1% Chance to ignite
Fire Trap: +1% Burning damage
Flicker Strike: +3% Critical Strike Chance
Freeze Mine: +0.5% AoE radius
Frenzy: +0.35 Attack speed per charge
Grace: +0.5% AoE radius
Hatred: +0.5% AoE radius
Haste: +0.5% AoE radius
Lightning Arrow: +1% Shock duration
Phase Run: +1% Increasesd melee physical damage
Poison Arrow: +1% AoE radius
Projectile Weakness: +0.5 Chance to pierce
Puncture: +1% Duration
Rain of Arrows: +1% AoE radius
Split Arrow: +1% Attack Speed
Temporal Chains: +0.35 Reduced movement, cast and attack speed
Viper Strike: +1% Duration; +0.5% Attack speed
Whirling Blades: +1% Attack speed

GREEN SUPPORT GEMS

Added Cold Damage: +0.35% Chance to freeze
Chance to Flee: +0.5% Chance to flee
Culling Strike: +0.35% Atack speed; +0.33% Cast speed
Faster Attacks: +0.35% Attack speed
Faster Projectiles: +0.35% Attack speed; +0.35% Cast Speed
Greater Multiple Projectiles: +0.35% Cast speed; +0.35 Attack speed
Increased Accuracy: +1% Critical strike chance
Increased Area of Effect: +0.35%
Lesser Multiple Projectiles: +0.33% Attack speed; +0.35% Cast speed
Mana Leech: +1% Mana leech rate
Pierce: +0.5% Chance of piercing
Point Blank: +0.5% Projectile damage
Trap: +1% Trap duration

This is what I could find so far. Please add bonuses in your posts and i will copy them into the list.

Thanks go to RabidRabbit and his thread (outdated): http://www.pathofexile.com/forum/view-thread/20284 and to all the posters in this thread.

When I found this it already had 7% quality on it so i'm not completely sure of how it breaks downs but it appears to add 0.5% chaos damage per 1% quality (assuming 3.5% is being rounded down to 3%).

Gotta love that Search Function.Skill gem level/quality reference (now in Google Doc form!)

My apologies. The linked thread is very old and i didn't notice it.

That is true.. I have no idea if Rabbid plans on updating it.. there's quite a few of the new skills that are missing.

Maybe it's a good idea if you continue the project.

I will take from his chart what he has and update with new info as it turns up.

Edit: Updated the list with all the available info and replaced outdated gems and data.

Summon skeletons are +1% damage per %.

knockback support gem is +2% knockback distance/upgrade

I'm not sure the exact change taking place but here's a 0% and 5% Firestorm for comparison.

Also, here's 2 Lightning Arrows for comparison.

And others that aren't listed.

Cold to fire:

14% increased cold damage
14% increased fire damage

@ Q20

Lightning Strike:

2% Chance to Pierce per 1% Q