Gems are divided by 4 different things:
Element
You want to put the same element as pet or you will get “only” 80% of the stats.
If you put Heroic Grade (purple) gems of the same element as your pet, you get Bonus Effects. These bonuses are always bonus damage and damage reduction over the element they have advantage in the damage chart chart.
Holy Gems are the exception, since they will instead give bonus damage to Holy enemies.
Shape
Shapes give Gem Set Effect. The more Gems you have with the same shape, the higher this % becomes.
- Round: +0.1% Crit Chance
- Square: +0.1% Block Chance
- Hexagon: Attack Amp +0.14%
- Octagon: Additional Damage +0.14%
All bonuses increases every 4 points on the chart shown below.
If you have the best possible gem you can achieve more than 1 effect since it gives 100 points but you get a small penalty overall to shape matching bonuses.
So you might want to keep the same shapes even at the very end. You need at least 2 gems to get the effect so you can’t get all four shape effects.
Grade
This refers to names of the categories in Gem tab: General, Uncommon, Rare, Heroic, Legendary.
A grade of the gem also can be understood by background colour and rarity: Grey, Green, Blue, Purple, Yellow.
Tier
This refers to number that is located on top left of the gem.
Tier is like sub category in Grade. There is 3 tiers in every Grade except for General and Uncommon. Tiers give increased Equip Effects which you can re-roll with Gem Chisel.
For example Rare Grade T1 Holy gem has 3.3% ATK on stat pool but Rare Grade T2 Holy Gem can give %4 ATK from stat pool.
Higher tier Gems also give more points towards the Set Effects chart.
There are 2 different Gem Merging you can do, but for both cases the Grade of the gems has to be same.
Tier upgrade merge
You can upgrade the Tier of a gem if you have 3 lower tier gems. Grade has to be same on all 3. For example you can merge three Uncommon Holy T1 gems into one Uncommon Holy T2 gem.
There is no Tier upgrade with General/Crude Grade gems. You only can do grade upgrade at lowest grade.
General grade gems only go up to T1, Uncommon ones go up to T2 while higher grades can go up to T3.
Legendary grade gems are an exception, upgrading from T1 to T2 or T2 to T3 only requires 2 gems instead of 3.
Grade upgrade merge
Once you get to maximum possible Tier of the grade you are allowed you can upgrade the lower grade gems into higher grade.
For most grades you will need 4 max tier gems. Heroic to Legendary is an exception, you only need 3 Heroic T3 gems to get 1 T1 Legendary Gem.
Another example with a lower grade; if you have 4 T2 Frost Uncommon Gems, you can merge these into one T1 Frost Rare Gem.
There is chance that new gem get random shape even if you use same shapes as merging. This chance seems to be low.
Just like gear, gems have substats (2 so far only from what we have seen).
However, in contrast to gear, you can actually lock one of the lines and just reroll the other one to get your desired stats.
- The top stat is always an offensive stat related one
- The bottom stat is always a defensive stat related one
The percentage they can give is based on the Grade and Tier of the gem. Since there are a few rarities, we recommend you check in-game with the information icon besides the gem name.
Rerolling stats costs Gem Chisel, which you can get in shops and Brawl gamemode. The cost of rerolling is also tied to the gem Grade and Tier.
We recommend you wait until Heroic grade gems at least, since those can give already Bonus Effects.
This allows you to change the Shape of a gem using Transformation Tickets. You can only do this starting from Heroic (purple) grade, lower grade gems cannot be transformed.
Transformation Ticket Cost
The number of tickets required depends on the gem’s Grade and Tier:
Getting Transformation Tickets
Currently the only two ways to get them is through the Exchange Shop, with a limited amount available to buy each month and in the premium shop where they are quite expensive.
Because of this, prioritize spending them on your highest grade gems and think carefully before using them.
Which Shape Should I Pick?
Round is widely considered the best shape, with Octagon being a solid alternative. Square should be avoided if possible.
The reason comes down to how the stats actually work: Crit Chance from Round gems converts into Crit Amp, which is a multiplicative modifier. Crit DMG from Square gems is additive.
Even when the numeric value of Crit Chance looks lower on paper, the multiplicative nature of Crit Amp makes Round significantly stronger overall.
If your gem is not Square shaped, it is generally usable. If it is Square, it is worth spending tickets to change it to Round. The value difference is large enough to justify the cost.