Why this lesson matters
The skill gems lesson covered the Skills Window, which replaced gear sockets for active skills and supports entirely. So what are the sockets still physically on your gear actually for? This is a completely separate system: Runes and Soul Cores.
Not the same "Runes" as the current league mechanic. If you've seen "Runes of Aldur," that's this league's crafting/Runeforging system (Runic Ward, Verisium, Kalguuran Skills) — see Runes of Aldur in the League track. This lesson covers the permanent gear-socket system: the Runes and Soul Cores you socket into Item Sockets. Different systems, same word, unrelated otherwise.
Item Sockets are a gear mechanic, not a skill mechanic
Gear pieces carry their own Item Sockets, distinct from anything in the Skills Window. How many a piece can have depends on its category:
- Chest Armour and Two-Handed Weapons: up to 2 sockets.
- One-Handed Weapons, Helmets, Gloves, Boots: up to 1 socket.
- Jewellery, Quivers, Belts, and Caster Weapons (wands, sceptres, staves): 0 sockets natively.
Runes vs. Soul Cores
Runes are the common version — they drop regularly through the campaign and early endgame, and you socket them into gear to patch specific gaps: a resistance that's short, some flat damage, that kind of thing. Think of them as a direct, targeted fix rather than a random roll.
Soul Cores are the rare, endgame-tier version of the same idea — Maxroll describes them as "a much more rare and difficult to obtain version of a Rune." They roll stronger and less common affixes: ailment scaling, crit bonuses, elemental penetration, Spirit-related bonuses, and rarity-adjacent modifiers, on top of the same kinds of stats Runes offer.
Worth stating plainly, since it's easy to wonder: Runes and Soul Cores go into the exact same Item Sockets — there's no separate socket type for either one. Any socket on your gear, whatever added it, will accept a Rune or a Soul Core interchangeably. The difference between them is acquisition and power tier, not socket compatibility.
Where Soul Cores come from: the Trial of Chaos — yes, the same Act 3 Ascendancy trial covered in Classes and Ascendancies. It does double duty: your first clear grants Ascendancy points, and running it (including repeat runs at higher difficulty) drops Soul Cores as loot, with better trial modifiers producing better cores. The Currency Exchange and player trading are secondary ways to get specific Soul Cores if you'd rather buy than farm, but the trial itself is the primary gameplay source.
Duplicates aren't dead weight. The Reforging Bench turns 3 of the same Rune (or 3 of the same Soul Core) into 1 random one of the same kind — see Exchanges for that and the other currency/crafting exchange mechanics PoE 2 actually has.
Getting sockets onto unsocketed gear
If a rare item doesn't have sockets, you can add them: salvaging a *socketed* item at the salvage bench yields Artificer's Shards, and 10 Shards combine into one Artificer's Orb, which adds an empty socket to an unsocketed item. It's a recycling loop — you're converting sockets you don't want on one item into sockets you do want on another.
Socketing isn't permanent anymore
This is worth knowing if you've read older POE2 content: early Early Access, socketing a Rune or Soul Core was permanent — no way to remove or replace it short of a Vaal Orb corruption. That changed in patch 0.1.1: you can now simply socket a different Rune or Soul Core over an existing one, and the old one is destroyed in the process. No Vaal Orb required, no un-socketing step — just overwrite it. The trade-off is destructive, not restrictive: you lose the old socketable, but you're never locked into a socket choice the way you used to be.
One correction worth flagging directly
If you've seen a claim that the Giant's Blood keystone grants extra item sockets (specifically, +2 sockets for dual-wielding), that's wrong — Giant's Blood is real, but what it actually does is let you wield two two-handed weapons at once (or a two-hander plus a shield), at the cost of tripled attribute requirements for those weapons. It has nothing to do with sockets.
Practical tips
- Don't hoard basic Runes during the campaign — since overwriting is now cheap and easy (no Vaal Orb needed), use them to patch resistance gaps as you find them rather than waiting for a "perfect" one.
- Salvage socketed white/magic gear specifically to build up Artificer's Shards early, rather than vendoring it outright.
- Save your best Soul Cores for your actual end-game gear, not a leveling item — since overwriting destroys the old socketable rather than freeing it back up, plan which item is getting your best core before you commit it.
- Don't expect a keystone to solve a sockets problem — sockets come from item base type and Artificer's Orbs, not passive tree keystones.
Sources: Maxroll — Runes and Soul Cores · Official PoE2 Wiki — Rune · Fextralife — Soul Cores · Fextralife — Runes · Mobalytics — Runes & Sockets · ArcaneStash — Runes, Soul Cores & Idols · GameRant — Soul Core Guide · GameRant — Giant's Blood · Official Path of Exile Forum — Patch 0.1.1 Notes