Gem upgrade will become available after completing instance 9-4 (chapter 9 - instance 4). This is one of the more complicated upgrades, and I will try to explain it as detailed as I can. So let’s begin:
-Magic, Rare and Legendary equipment pieces can be embedded with a gem. Magic weapons don’t have gem slots but Rare and Legendary weapons do.
-There are 5 types of gems: red, blue, purple, yellow and green. The color of the gem doesn’t represent gem Tier or quality, rather it represents gem type, and depending on the type of gem it can have certain attributes and can be inserted into a slot of a matching color. This means that the gem must be of the same color as the equipment slot color. NOTE: One gem can have only one attribute, randomly drawn from the following list:
-Red gem: Earth Resist, Wind Resist, Lightning Resist, Crit Resist, Crit Reduction, Accuracy
-Blue gem: Fire damage, Poison Damage, Freezing Damage, Crit, Crit Damage
-Purple gem: Defense, Attack, Elemental Attack, Dodge
-Yellow gem: Fire Resist, Poison Resist, Ice Resist, HP, Penetration, Damage Reduction
-Green gem: Earth Damage, Wind Damage, Shock Damage, Block, Damage Bonus
Different pieces of equipment will require the different type of gems, also not all equipment pieces have the same amount of gem sockets.
Gems of a different quality have a different shape. In the image above, blue and purple gems are Dim quality gems, while red, yellow, and green are Flawless quality gems.
You can gain gems through gem extraction, one random gem will be received per extraction, so luck is a major factor here. Every day you can extract gems 3 times for free, next 2 extractions will cost 2 Diamonds each, and after that, all extractions will have increasingly higher cost. You can perform extraction up to 150 times per day (more for VIP Accounts). Each time you extract a gem, you will be awarded Points (one of the in-game currencies). For every free extraction you’ll gain 2 Points, and also 1 Point per Diamond spent on extractions. These points can be spent at the Store to buy high tier gems, equipment, mount equipment, or runes.
Gems have 4 Tiers, you can tell the difference between them by the color of the attribute bonus (text) and maximum upgrade level:
-Rough Gem: Can be upgraded up to level 10
-Dim Gem: Can be upgraded up to level 15
-Flawless Gem: Can be upgraded up to level 20
-Shining Gem: Can be upgraded up to level 30
Only higher Tier Gems should be upgraded (Flawless and Shining), so upgraded costs of Rough and Dim gems won’t be shown in this guide. In order to upgrade a gem, you’ll need gem powder. It can be obtained through refinery of excess, usually low level, gems. More gem powder will be extracted from higher Tier Gems.
Flawless Gem upgrade cost:
Level 1 to Level 2 = 35 Gem Powder.
Every upgrade after the first one will increase the cost by 35 gem dust (70 gem dust for level 3, 105 for level 4, 140 for level 5… 1425 for level 20)
Shining Gem upgrade cost:
Level 1 to Level 2 = 40 Gem Powder (example attribute bonus +100 attack)
Every upgrade after the first one will increase the cost by 40 gem dust (80 gem dust for level 3, 120 for level 4, 160 for level 5… 1160 for level 30).
Attribute increase example: Attack bonus will increase by +100 every level, so at level 5 total bonus would be +500 attack. So, to summarize: The cost will progressively increase while the attribute bonus per gem level will increase at the same rate, making this a high-cost upgrade (but still a very useful one)