Listed in order of the gem trader menu,
Elemental
红宝石 (Red Gem) Enchant Weapon: Adds element fire, +15% apply "burning" status Enchant Armor: fire element 90% as effective, "burning" status 90% as effective
蓝宝石 (Blue Gem) Enchant Weapon: Adds element ice. +15% apply "frozen" status Enchant Armor: ice element 90% as effective, "frozen" status 90% as effective
暗之石 (Dark Gem) Enchant Weapon: Adds element dark, +15 % apply "darkness" status Enchant Armor: dark element 90% as effective, "darkness" status 90% as effective
猛毒之石 (Poison Gem) Enchant Weapon: Adds element poison, +15% apply "poisoned" status Enchant Armor: poison element 90% as effective, "poisoned" status 90% as effective
圣光宝玉 (Holy light Gem) Enchant Weapon: Adds element holy Enchant Armor: holy element 90% as effective
疾风勾玉 (Gale Magatama) Enchant Weapon: Adds element wind, +15% apply "silenced" status, +20 attack speed Enchant Armor: wind 90% as effective, "silenced" status 90% as effective
雷之勾玉 (Thunder Magatama) Enchant Weapon: Adds element electric, +15% apply "stunned" status Enchant Armor: electric 90% as effective, "stunned" status 90% as effective
地之石 (Earth Gem) Enchant Weapon: Adds element earth, +15% apply "dizzy" status Enchant Armor: earth 90% as effective, "dizzy" status 90% as effective
Mid-tier
伤之石 (Wound Gem) Enchant Weapon: Adds element physical, +15% apply "bleeding" status Enchant Armor: "bleeding" 90% as effective
血之石 (Blood Gem) Enchant Weapon: +4% lifesteal Enchant Armor: +3%HP regen, drain 90% as effective
破甲之石 (Armorbreak Gem) Enchant Weapon: Adds element physical, +20% apply "armorbreak" status Enchant Armor: +5% Defense
牙之石 (Tooth Gem) Enchant Weapon: Adds element physical, +5% attack Enchant Armor: physical 95% as effective
破坏之石 (Destruction Gem) Enchant Weapon: Adds element physical, +3% critical rate Enchant Armor: +4% critical avoid
魔能之石 (Mana Gem) Enchant Weapon: +4% magical Attack Enchant Armor: +5% Magical defense, +5% MP regen
High-tier
紫电魔晶(Violet Lightning Crystal) Enchant Weapon: Adds element electric, +25% apply "stunned" status Enchant Armor: "stunned" status 70% as effective, +1% avoid, electric element 80% as effective
冰魔晶 ( Ice Crystal) Enchant Weapon: Adds element ice, +25% apply "frozen" status Enchant Armor: ice element 70% as effective, "frozen" status 65% as effective
火魔晶 (Fire Crystal) Enchant Weapon: Adds element fire, +25% apply "burning" status Enchant Armor: fire element 70% as effective, "burning" status 65% as effective
黑曜石 (Obsidian) Enchant Weapon: Adds element physical, +40% apply "armorbreak" status Enchant Armor: +5% defense, physical element 95% as effective, +5% magical defense
Not yet in the menu
精准之石 (Accuracy Gem) Enchant Weapon: +10% Hit rate, +1% critical rate Enchant Armor: +3% avoid
Ultimate gems obtained from some Saint Adeline quest
剧毒魔珠 (Venomous Orb) Enchant Weapon: Adds element poison, +30% apply "poison" status, +15% apply "stunned" status Enchant Armor: poison element 60% as effective, "poisoned" status 50% as effective, "stunned" status 50% as effective
烈焰魔珠 (Flame Orb) Enchant Weapon: Adds element fire, +35% apply "burning" status Enchant Armor: fire element 60% as effect, "burning" status 50% as effective
寒冰魔珠 (Ice Orb) Enchant Weapon: Adds element ice, +35% apply "frozen" status Enchant Armor: ice element 60% as effective, "frozen" status 50% as effective