Legendary Gems

Legendary Gem interface window.

Legendary Gems (or LGems or LeGems) were added to Reaper of Souls in Patch 2.1, after extensive testing on the PTR. There were initially 14 types of Legendary Gems, with more added each Season. Most Legendary Gems have a function only when socketed in rings and amulets, this makes rings and amulets with sockets highly sought.

Rules of Drop and Use

Legendary Gems are only dropped from Greater Rift Guardians, the final bosses of Greater Rifts. A Gem is guaranteed to drop if the player doesn't have on in his equipment, inventory or stash. This guarentees that a player will get all Legendary Gems without having to rely too much on the RNG. Duplicates are only possible if another character takes a Gem out of the stash.

All gems are dropped at rank 0 and must be socketed into a ring or amulet, making such rings and amulets valuable. Players can use the Mystic to add sockets to ring and amulets they like. Socketing and removing work the same as with normal Gems.

Legendary Gems come with an effect with an upgradeable value in it. Each rank the gem gains increases the value by a set amount. Gems are upgraded by Urshi after completing a Greater Rift within 15 minutes. Players get 3 chances to upgrade gems for each rift. Upgrade odds are based on Gem Level and Greater Rift Level. When both are equal, the chance is 60%. When the Greater Rift is more than 6 level higher, the chances up, topping out at 100 % at 10 levels. If the Gem is higher, the chance is halved for each rank of difference. The max gem rank is 200, far beyond the highest Greater Rift Clear.

Upgrade Odds

GRift level vs. Gem Level	+10	+9	+8	+7	+6	+5	+4	+3	+2	+1	0	-1	-2	-3	-4	-5	-6	-7
LGem Upgrade Chance	100%	90%	80%	70%	60%	60%	60%	60%	60%	60%	60%	30%	15%	8%	4%	2%	1%	0%

Examples:

GRift level 17, LGem level 5 = +12 = 100% chance of successful upgrade.
GRift level 22, LGem level 14 = +8 = 80% chance of successful upgrade.
Grift level 22, LGem level 24 = -2 = 15% chance of successful upgrade.

Note that the odds recalculate with each successful upgrade, so a gem rolling successfully could be 100% on the first try, 90% on the second, and 80% on the third.

Legendary Gems Catalog

Effect	Values	Rank 25 Bonus	Notes
Bane of the Powerful
Gain 20% increased damage for X seconds after killing an elite pack.	Start:25 Increase:1	15% Increased Damage to Elites	One of the most popular gems, this grants a big damage buff, works with every type of build, and enjoys around 100% up-time in Rifts, where Elites abound.
Bane of the Stricken				Need Pic
Each attack you make against an enemy increases the damage it takes from your attacks by X%	Start: 0.8% Increase: 0.01%	Gain 25% increased damage against Rift Guardians and bosses	This gem was added for Season 4	Need Pic
Bane of the Trapped
Increase damage against enemies under control-impairing effects by X%	Start: 15% Increase: 0.3%	Gain an aura that reduces the movement speed of enemies within 15 yards by 30%.	The Aura at Rank 25 has no visual display, but it does proc the gem itself; so monsters near the hero are slowed and thus take increased damage.
Boon of the Hoarder
X% chance to cause an explosion of gold when you kill an enemy	Start: 25% Increase: 1.5%	Gain 30% increased movement speed for 2 seconds after picking up gold.	The first time found (on an account) it will only drop from Greed, found in The Vault.
Enforcer
Increases the damage of your pets by X%	Start: 15% Increase: 0.3%	Your pets take 25% reduced damage.	The rank 25 bonus is irrelevant for pets that are not targeted and do not take damage, such as Hydras or Sentries.
Esoteric Alteration
Gain X% non-Physical damage reduction	Start: 10% Increase: 0.5%	While below half Life, your resistances to Cold, Fire, Lightning, Poison, and Arcane are increased by 75%.	A very powerful defensive gem, added in Season Two.
Gem of Ease
Monster kills grant +X experience	Start: 500 Increase: 50	Level requirement reduced to 1	Sockets into Weapons rather than jewelry. Useful for twinking
Gem of Efficacious Toxin
Poison all enemies hit for X% weapon damage over 10 seconds.	Start: 1000% Increase: 50%	All enemies you poison take 10% increased damage from all sources.	A popular gem for big damage over time, but less useful for characters who kill enemies very quickly. One of the more powerul Rank 25 bonuses
Gogok of Swiftness
50% chance on hit to gain Swiftness, increasing your Attack Speed by X% for 4 seconds. This effect stacks up to 15 times.	Start: 1% Increase: 1%	Gain 1% Cooldown Reduction per stack of Swiftness	The Attack Speed increase is useful to some builds, but this gem is most valued for the massive CDR granted by the Rank 25 property.
Iceblink				Need Pic
Your Cold skills now apply Chill effects and your Chill effects now slow enemy movement speed by an additional X%	Start: 5% Increase: 0.4%	10% increased chance to critically strike Chilled or Frozen enemies	One of two gems added in Season Three	Need Pic
Invigorating Gemstone
While under any control-impairing effects, reduce all damage taken by X%	Start: 30% Increase: 0.4%	Heal for 20% of maximum life when hit by a control-impairing effect.	As with the other original batch of defensive gems, this is one of the least-used gems.
Mirinae, Teardrop of the Starweaver
15% chance on hit to smite a nearby enemy for X% weapon damage as Holy.	Start: 1000% Increase: 40%	Smite a nearby enemy every 5 seconds	The smite can hit virtually any enemy on the screen, making the "nearby" description fairly inaccurate. On the whole this adds huge damage to individual targets, but not as much to large groups compared to other gems
Molten Wildebeest's Gizzard
Regenerate X Life per Second	Start: 10000 Increase: 1000	After not taking damage for 4 seconds, gain an absorb shield for 200% of your total Life per Second.	Another powerful defensive gem added in Season Two. This gem synergizes well with defensive buffs that prevent the character from taking damage, and the Rank 25 power can fuel itself, as the shield keeps the player from taking damage.
Moratorium
25% of all damage taken is instead staggered and dealt to you over X seconds.	Start: 3 Increase: 0.1	10% chance on kill to clear all staggered damage.	Another of the initial batch of defensive gems that proved little-used.
Mutilation Guard				Need Pic
Gain X melee damage reduction.	Start: 10% Increase: 1%	Below 50% life, you may move through enemies unhindered	A Defensive Gem added in Season 3	Need Pic
Pain Enhancer
Critical hits cause the enemy to bleed for X% weapon damage as Physical over 3 seconds.	Start: 500% Increase: 30%	2% increased Attack Speed for each bleeding enemy within 20 yards.	Best used with character with high Crit chance and AOE attacks.
Simplicity’s Strength
Increase the damage of primary skills by X%	Start: 25% Increase: 0.5%	Primary skills heal you for 2% of maximum health on hit.	Probably the least used offensive gem from the initial batch, as primary skills are so weak compared to Spenders.
Taeguk
Gain 0.5% increased damage for 3 seconds after spending primary resource. This effect stacks up to X times	Start: 20% Increase: 1	Gain 0.5% increased Armor for every stack.	This gem adds huge damage when fully stacked, but the stacks take quite a while to build up, and any lull of just 3 seconds resets them to zero. The Rank 25 property is a powerful defensive bonus, especially for melee characters who can keep it stacked and active.
Wreath of Lightning
15% chance on hit to gain a Wreath of Lightning, dealing X% weapon damage as Lightning every second to nearby enemies. Lasts for 3 seconds.	Start: 600% Increase: 10%	While under the effect of the Wreath of Lightning, gain 25% increased movement speed.	A mini-Conduit Pylon, this gem zaps all nearby enemies for considerable damage. Radius is limited so close proximity to enemies is preferred.
Zei’s Stone of Vengeance
Damage you deal is increased by X% for every 10 yards between you and the enemy hit. Maximum 20% increase at 50 yards	Start: 4% Increase: 0.05%	20% chance on hit to Stun the enemy for 1 second.	The damage boost is calculated when damage is dealt, so movement changes the amount.

LGem Popularity

Legendary Gems were immediately embraced by players as a powerful new feature in the game, and sockets in jewelry became immediately sought after as mandatory end game affixes. Of all the gems, the offensive ones were the most popular and most used, since killing things faster is almost always the best and most fun strategy in Diablo III.

As for defensive legendary gems, even in Hardcore they were hardly used, which prompted much bigger defensive bonuses on the gems in the second batch, Esoteric Alteration and Molten Wildebeest’s Gizzard, added in Season Two.

Gem Upgrade Development

The system was under construction all throughout the PTR and saw major changes during July and August, 2014.

Gems initially had 50 ranks, with the odds to upgrade[1] increasing on higher Greater Rift levels. This was reworked after a few weeks, and a patch on August 5, 2014 changed the maximum level from 50 to 200 and greatly increased the odds for multiple rank boosts per upgrade, as well as granting multiple upgrade opportunities on higher level greater rifts. ^[1]

Legendary gems now start at rank 0

Changes have been made to the frequency at which Legendary gems are upgraded
- Note: Because of this change the power of each upgrade has been reduced, but the overall rate at which gem power is gained through upgrades should remain roughly the same

That system was changed again late in the PTR, with the ranks cut from 200 to 25, and a whole new system of upgrade odds implemented, based on the difference in level between the gem and the Grift. Those odds were the final system which went live a few weeks later.

Legendary Gem Design Theory

Legendary Gem upgrade interface.

Blizzard's John Yang explained the design theory behind Legendary Gems while they were being tested on the PTR, July 15, 2014. ^[2]

Hi everyone. I wanted to pop in here while discussion on Legendary gems is ongoing.

First off, our philosophy on Legendary gems is that, when you pick one up for the first time, you should immediately want to use it, assuming it’s for your build, since some gems don’t apply to all builds/needs. This puts a minimum bar on the starting power level. After that, the power increase per upgrade is directly related to the frequency of upgrading, which is closely tied to the Greater Rift reward scheme and is still being iterated on. In the end, we’d like gems to be infinitely upgradeable when it makes sense, but not be outrageous.

Additionally, all Legendary gems have been disabled for followers. These powers were not designed for followers in mind, and this way we can ensure the gems are of a high power level because you can only have 3 equipped. In the future, if followers need avenues of advancement we would likely make Legendary gems specifically designed for them.

Now for the details. The existing stats you see on Legendary gems on the PTR today are somewhat placeholder. So, to steer further discussion in a direction that’s more in line with the next PTR build, here are the freshly tuned numbers (with some of my notes) for each gem.

Official Reveal

Legendary Gems were first revealed in June 2014 and the first official info came from Blizzard's Patch 2.1 preview blog. ^[3]

Legendary Gems are still undergoing significant iteration at this time, so you won’t see them available on the PTR right away. The gist is that these gems are infinitely upgradeable, and provide special Legendary powers when socketed into the appropriate gear slot. They can only be socketed into Rings and Amulets, and can be upgraded by completing additional Greater Rifts. The higher you place in a Greater Rift, the more likely your gem will be successfully upgraded. We’ll have more details in the future as we continue development on these powerful baubles, so stay tuned!