Hardmode Ore Farming in Terraria — Cobalt, Mythril & Adamantite Guide

How Hardmode Ores Spawn — The Altar System

When you defeat the Wall of Flesh and enter Hardmode, new ore does not automatically fill your world. Instead, it is unlocked by breaking Demon Altars (in Corruption worlds) or Crimson Altars (in Crimson worlds) with the Pwnhammer — the drop from the Wall of Flesh. No other hammer can break Altars.

Each Altar you break spawns a 'vein' of ore somewhere in the world, following a strict pattern: 1st Altar → Cobalt or Palladium ore, 2nd Altar → Mythril or Orichalcum ore, 3rd Altar → Adamantite or Titanium ore. This pattern repeats — the 4th Altar gives more Cobalt/Palladium, 5th more Mythril/Orichalcum, and so on. However, each additional Altar cycle spawns fewer veins than the previous.

Which variant you get (Cobalt vs Palladium, etc.) is determined randomly when your world was generated — each world has exactly one of each pair. Breaking more Altars spawns more veins of your world's specific variants. You cannot get both Cobalt and Palladium in the same world through normal play.

Hardmode Ore Tiers — Stats & Requirements

Best Methods for Farming Hardmode Ores

Method 1 — Horizontal Tunneling: Create long, flat tunnels at multiple depths through the underground cavern layer (roughly 500–1,500 tiles underground depending on world size). Ore veins are randomly distributed throughout the underground, so long horizontal corridors with good lighting reveal veins through the visible cave walls. This is the most thorough method but time-consuming.

Method 2 — The Hellevator Method: Dig a vertical shaft from the surface to the Underworld (a 'Hellevator'). As you dig down, the tunnel naturally passes through multiple underground layers where ore veins cluster. Use torches to light the shaft and look for colored ore deposits on the shaft walls. Return to collect all highlighted ores after scanning the full depth.

Method 3 — Spelunker Potion Sweeps: Craft Spelunker Potions (Bottled Water + Blinkroot + Moonglow + Gold Ore) and use them before mining sessions. Spelunker Potions highlight all nearby ores and valuable items through terrain for 5 minutes. Walk through cave networks you have already dug while under the Spelunker buff to spot ore veins you missed. This is the most resource-efficient method for targeted farming.

Method 4 — Surface Ore Exposure: Break enough Altars to spawn many ore veins, then strip-mine horizontal corridors in the stone/cavern layer. This combines with the Spelunker Potion method to efficiently cover large underground areas. The best depth for ore farming is the cavern layer (600–1,500 tiles underground on large worlds).

How Many Altars Should You Break?

• Break at least 3 Altars to spawn all three tiers of ore. This is the minimum for unlocking Cobalt, Mythril, and Adamantite in your world.
• Breaking 6 Altars (two full cycles) doubles the ore veins while the spawns remain reasonably abundant. This is the sweet spot for most players.
• Breaking too many Altars has a downside: each broken Altar has a chance to corrupt one random grass or stone block in your world, slowly spreading your evil biome. In large quantities, this can damage your Jungle or other biomes. Break no more than 12–15 Altars to avoid significant biome corruption.
• If you need more ore after 6 Altars, consider the surface ore exposure method rather than breaking many more Altars.

Smelting Chain — Processing Ores Into Bars

Each tier of Hardmode ore requires a specific furnace. The Mythril/Orichalcum Anvil (crafted from Cobalt/Palladium Bars) can smelt Mythril and Orichalcum ores, but Adamantite and Titanium require the Adamantite/Titanium Forge (crafted from 30 Adamantite/Titanium Ore + 1 Hellforge). Plan your smelting chain: mine enough Tier 1 ore to craft the anvil and pickaxe, then mine Tier 2 ore to craft the Tier 2 pickaxe needed for Tier 3 ore.

Bar quantities per armor set (approximate): Cobalt Armor requires 54 Cobalt Bars (162 Ore). Mythril Armor requires 45 Mythril Bars (180 Ore). Adamantite Armor requires 54 Adamantite Bars (270 Ore). Plan your farming sessions accordingly — Adamantite requires the most ore to fully kit out in that tier.

Prioritize weapons alongside armor. The Cobalt Sword/Palladium Sword and Cobalt Repeater/Palladium Crossbow are immediate upgrades over pre-Hardmode weapons. Each ore tier's pickaxe is also critical — you cannot mine Tier 2 ore without a Tier 1 pickaxe or drill.

Cobalt vs Palladium and Mythril vs Orichalcum — Which Is Better?

Verdict: The Crimson variants (Palladium, Orichalcum, Titanium) are generally considered stronger for most builds due to better defensive or proc mechanics. However, both variants are perfectly viable for clearing all Hardmode content — the difference is a matter of playstyle rather than clear superiority.