Gems are a vital tool in Xenoblade Chronicles, allowing the party to get stronger and be able to defeat many of the strongest bosses this game can offer. Some of them may be underwhelming, but with a good combination, your party will be able to beat the hardest of monsters with little effort.
One can acquire gems in many different ways, such as finding them as monster loot, as rewards for completing a quest or a section of the Collectopaedia, or by trading with an NPC. Gems can also be upgraded at Ether Furnaces, but some characters can make better use of some gems than others. This will help you get through the game faster so you can play the also beloved sequel.
10 Spike Defence – Fiora
Fiora is one of the best party members in the game, and can hit really hard with Auto-Attacks when equipped properly. However, there are some enemies in Xenoblade (and most super bosses) that have a property called Spikes. A foe with Spikes will damage anyone who attacks them, and it can become a real hassle in long and difficult fights.
As one of the best damage dealers, Fiora benefits greatly from Spike Defence gems, which prevents up to 75% damage that a Spiked enemy would deal when attacking it. This can increase Fiora's survivability and will also allow her to deal more damage without having to worry too much about her health.
9 Ether Up – Melia
Melia covers the stereotypical Mage archetype in Xenoblade Chronicles. She can blast her enemies with powerful spells and Arts, but has reduced defense and heath. Her high Ether stat can benefit greatly from any increases so that her already incredibly strong spells can destroy any boss' health bar rapidly.
Alongside her Ultimate Ether skill, equipping Melia with an Ether Up Gem will transform her into an superbly mighty sorcerer. Her arts will help all you buff the party and summon powerful beings to aid in battle. Simply a must have for Melia.
8 Topple Resist – Riki
Topples are one of the most annoying and dangerous debuffs the party can encounter in the game. These disable your party members as if they were stunned and they can't do anything for a few seconds. This is especially dangerous considering this gives enemies time to charge up strong, unavoidable moves.
A level 6 Topple Resist Gem will make the character equipped with it immune to all Toppling, which Riki can really benefit from. He is very bulky, so taking hits doesn't bother him too much. Resisting Topples will allow him to keep inflicting debuffs on the enemy and slowly but surely get rid of their HP bar, along with distracting foes from damaging more vulnerable allies.
7 Double Attack – Dunban
Double Attack is a very straightforward Gem, it gives the character it's equipped to a chance to Auto-Attack twice instead of once. This directly increases the DPS of party members that rely more on attacking directly instead of Arts to deal damage, making Dunban the ideal candidate.
The Deinos Sauros found in Makna Forest are a great enemy to get Crystals and Cylinders to craft this Gem. It's definitely one of the best Gems to give Dunban, though Fiora can also benefit lots from it. The chance to Auto-Attack twice may not sound like a big deal at first but this will bump up Damage dealt tremendously.
6 Heat Sink – Sharla
The Sniper-Wielding Medic fills the role of a healer in Xenoblade Chronicles, but she has one major flaw: Her sniper overheats easily and this leaves her unable to use Arts, meaning all the hard work put into levelling and heart-to-hearts with her can feel wasted. Even with her Cool Off talent, she can sometimes get out of hand.
Luckily for her, there's a Gem made for her and her only; Heat Sink decreases the rate her Ether Rifle heats up at, allowing her to perform more actions like Attacking and buffing her party without having to wait for the tiresome cooldown times.
5 Phys Def Down – Shulk/Dunban
This Gem is a must have if you're also using Double Attack. This gives your character's Auto-Attacks a chance to lower the target's Def stat, which is extremely useful in long-lasting battles, and will give your team a powerful edge against the toughest Bosses.
This Gem is especially good for (spoiler warning) Monado wielders, Shulk and Dunban, since their Arts (Slit Edge and Worldly Slash respectively) stack with this buff, aiding them to deal more & more damage throughout the fight. This combination can make some battles trivial and will definitely help in your quest.
4 Debuff Resist – Anyone
Debuffs are one of the most annoying things players will encounter in Xenoblade Chronicles, as they force the party to keep wasting Arts to get rid of them only for debuffs to crop up again. Luckily, there's a solution: Debuff Resist is a Gem that increases resistance to all Debuffs and the highest level iteration of this Gem can even make party members immune to them!
This beauty works wonders on anyone, since having everyone in your party be immune to Debuffs is a massive advantage that will make your team feared across the Bionis and the Mechonis. It is vital to remember that this Gem, despite being spectacular, does not protect your party against Topple and Daze, since they are not considered Debuffs.
3 Attack Stability/Attack Plus – Fiora
These two Gems are truly outrageous. Attack Stability increases your minimum Attack damage and Attack plus increases your Maximum attack damage. When used in coordination, they can produce devastating results for enemies since it increases attack with no detriment.
Our beloved knife-wielding childhood friend would benefit greatly from this. Her Arts work perfectly with higher Attack and can decimate enemy forces with ease. Easily one of the best Gem combinations out there, they are never a wasted slot in your repertoire.
2 Haste – Dunban
Haste is a simple but powerful Gem that can turn the tide of battle when equipped to the right party member. Dunban, the Hero of the Homs, is proficient in wielding swords and this Attack Speed enhancing Gem can do him lots of good.
When combined with other Attack-Enhancing Gems such as Double Attack or Phys Def Down, this can become one of the strongest Gems you'll get for Dunban. He will stand up to the toughest challenges and truly be the Hero worthy of his title.
1 Topple Plus – Shulk
Every hero can benefit from what may be the best Gem in the game, but the beloved protagonist may be the one that can use its function to the fullest. Topple Plus will help you and your party blast through most if not all Super Bosses in the game if you are having a tough time.
Shulk's Monado Cyclone may be used to activate this Gem, which increases the duration of Topple on Enemies. If multiple Party Members hold this powerful Gem at the same time, it can be used to combine several Toppling Arts to lock the enemy in a position where they cannot take actions.