Mythril ore can be gathered in the Sagolii Desert in Southern Thanalan (X:25.5, Y:40.7), specifically by players with the miner class. And these Mythril mining points are level 35, so you need to be at least level 31 to find them.
This area of the Sagolii Desert is in the Southeast corner of the map.
The quickest way to get there would be through the Forgotten Springs aetheryte in Southern Thanalan.
And this little corner of the map is relatively safe, since it’s a camp inhabited by an NPC named Hab. So there aren’t any monsters around.
But you may get attacked on the way here, since there are aggressive monsters in surrounding area – such as level 32 sundrakes between the mining points and the aetheryte.
Mythril ore can also be collected as a reward from levequests or mined by your retainers. I would suggest mining them yourself though, since it’s the fastest and most consistent method to get more (outside of purchasing the ores directly).
Cimeaurant, Coerthas Central Highlands (X:26.1, Y:28.3)
Colder Than Steel (Lv. 35 Blacksmith)
Dead Can’t Defang (Lv. 35 Goldsmith)
Faith and Fashion (Lv. 35 Goldsmith)
I’ve Got You Under My Skin (Lv. 35 Armorer)
Lending a Hand (Lv. 35 Blacksmith)
Seemed Like the Thing to Get (Lv. 35 Blacksmith)
Skillet to the Stars (Lv. 35 Armorer)
War Is Tough on the Hands (Lv. 35 Armorer)
Wear Your Patriotic Pin (Lv. 35 Goldsmith)
Voilinaut, Coerthas Central Highlands (X:12.7, Y:16.8)
Employee Retention (Lv. 40 Armorer)
Family Secrets (Lv. 40 Armorer)
Get Me to the War on Time (Lv. 40 Blacksmith)
Kitchen Casualties (Lv. 40 Blacksmith)
Metal Fatigue (Lv. 40 Armorer)
Streamlining Operations (Lv. 40 Blacksmith)
Nahctahr, Eastern La Noscea (X:30.5, Y:30.9)
Get the Green Stuff (Lv. 30 Goldsmith)
It’s Only Love (Lv. 30 Goldsmith)
Renascence Man (Lv. 30 Goldsmith)
Keep in mind that mythril ore isn’t always going to be rewarded from these quests.
The item rewards from levequests change randomly every time you take one from an NPC.
Exploration Ventures For Ores
Ventures are like assignments you give to your retainers to gain experience, or to farm items for you.
When a retainer is set to being a miner, you can send them out on Mining Exploration Ventures.
These are ventures where you can assign your retainer a specific item to farm – such as Mythril Ores.
Exploration ventures last for 1 hour, but this can be reduced by up to -20 minutes by leveling your retainer further. The minimum level required for the mythril ore venture is level 34.
These NPC assistants of yours can bring back 15 to 50 pieces of ore per run, depending on their perception stat. Having a perception of 224 will guarantee 50 pieces of mythril ore every time your retainer comes back.
Mythril ores are used mainly by blacksmiths, armorers, and goldsmiths to create mythril ingots and mythril nuggets.
These two items are essential in crafting several other items, like housing items, accessories, and weapons (such as the Inferno Rod, pictured above).
To craft mythril ingots, you’ll need:
x3 mythril ores
Plus x4 shards of either ice, fire or wind, depending on which class you’re on
For mythril nuggets, you’ll need
x1 mythril ore
x5 pinches of mythrite sand
x3 shards of ice, fire or wind
Mythril ore can also be turned in for your daily miner provisioning mission. 10 pieces will be requested from your Grand Company Personnel Officer at level 34.
