Gems can be arranged in your gem frame to modify many statistics and weapon/item behaviors in the game. You're limited by the available space in your gem frame (which expands through various quests in the game), and the orientation of that space within the frame (ie if you have 2 empty spaces you may be able to put in a 2x1 gem but not a 1x2 gem, depending on the arrangement of the current gems in the frame).
Some gems are found or purchased throughout the game (or won as quest rewards), while others must be fused from other gems. Some gems can be created with more than one formula, and when known this should be indicated in the tables below. Costs listed may be the cost of fusion or the cost to purchase from the vendor, depending on availability.
The number of gems you can carry (besides those in your gem frame) is determined by the type of knapsack you have, and is the same as the number of any other type of item you can carry (8 to 24). Therefore, if you have the basic knapsack you start the game with, you can carry 8 of each type of gem (individual gem types, not just 8 within each color of gem).
Purple Gems (affect Fury and special attacks) 15 types
| Gem Type | Description | Cost | Size |
|---|---|---|---|
| Glittering Crystal | DEX (critical hit probability) +10 | 1000 | 1x1 |
| Cruel Sword | When you are in Fury, your focused sword attacks reach level 2 | 1x1 | |
| Cruel Flail | When you are in Fury, your focused flail attacks reach level 2 | 1x1 | |
| Cruel Bow | When you are in Fury, your focused bow attacks reach level 2 | 1x1 | |
| Cruel Hammer | When you are in Fury, your focused hammer attacks reach level 2 | 1x1 | |
| Fury Reels | Enables Fury Reels when you enter Fury | 2x1 | |
| Morale Boost | Makes the Fury gauge fill faster | 4000 | 2x1 |
| Ruthless Sword | When you are in Fury, your focused sword attacks reach level 3 | 4000 | 2x1 |
| Ruthless Flail | When you are in Fury, your focused Flail attacks reach level 3 | 4000 | 2x1 |
| Ruthless Bow | When you are in Fury, your focused hammer attacks reach level 3 | 3000 | 2x1 |
| Ruthless Hammer | When you are in Fury, your focused hammer attacks reach level 3 | 3000 | 2x1 |
| Ruthless Gemma | When you are in Fury, all focused attacks reach level 3 | 2x2 | |
| Spirit of the Hero | Doubles duration of Fury | 5000 | 2x2 |
| Double Fury | Doubles experience earned while in Fury | 3x2 |
Orange Gems (affects items and EXP gained) 7 types
| Gem Type | Description | Cost | Size |
|---|---|---|---|
| Lore of Thieves | Makes fake treasure chests appear as monsters on radar | 1000 | 1x1 |
| Drain Will | Converts 3% of damage inflicted on monsters into MP | 15000 | 1x2 |
| Drain Life | Converts 3% of damage inflicted on monsters into HP | 30000 | 2x1 |
| Lore of Niccolos | Adds 10% bonus to lucre gained | 4000 | 2x2 |
| Heart of Progress | Increases experience gain by 50% | 10000 | 2x2 |
| Double Drop | Doubles the chance that monsters will drop items and lucre | 5000 | 2x2 |
| Drain Soul | Converts 3% of damage inflicted on monsters into HP and MP | 35000 | 2x2 |
Green Gems (nullify status ailments & spikes) 12 types
| Gem Type | Description | Cost | Size |
|---|---|---|---|
| Purity's Shelter | Prevents you from being poisoned | 8000 | 1x2 |
| Flame's Shelter | Prevents you from catching fire | 4000 | 1x2 |
| Water's Shelter | Prevents you from being turned into a snowman | 4000 | 1x2 |
| Forest's Shelter | Prevents you from being put to sleep | 4000 | 1x2 |
| Moon's Shelter | Prevents you from being confused | 4000 | 1x2 |
| Light's Shelter | Prevents you from being stunned | 4000 | 1x2 |
| Shadow's Shelter | Prevents you from being blinded | 4000 | 1x2 |
| Earth's Shelter | Prevents you from being disarmed | 4000 | 2x1 |
| Wind's Shelter | Prevents you from being paralyzed | 4000 | 2x1 |
| Virtue of Safety | Enables safe travel over spikes | 6000 | 2x2 |
| Virtue of Balance | Enables steady travel over sand and ice | 6000 | 2x2 |
| Ultimate Protection | Prevents all ailments | 12000 | 3x2 |