Socketing
Socketing is done at a jeweler's bench (the “Sockets” button). A spare element gem pressed into a piece of armour or jewelry gives +4% resistance to that element.
- Gems:
Poison Gem, 
Earth Gem, 
Storm Gem, 
Holy Gem, 
Dark Gem, 
Cut Bloodstone, 
Cut Glacite → Poison, Earth, Storm, Holy, Dark, Fire and Frost resistance. - Only forged or found (generated) armour and jewelry has a socket. Uniques, fixed set pieces and hand-made starter gear do not.
- One socket per piece: socketing a second gem replaces (and destroys) the first. You cannot put the same element in twice.
- The gem is stored in the item, so it stays with the item.
- Resistance is capped at 75% in total (including gear, titles and talents).
See also the Socketing guide, and Resists.