Gem

Gem is an item which can be placed into an item's socket slot. After a gem is placed it cannot be removed and can only be overwritten. Gems are made in Jewelcrafting.

Gem Stats
Gems are split into 3 categories: Blue, Yellow and Red. Also there are Meta gems that can only be place in Meta socket slot. Here is a table to see which gem color gives which stats. There are also mixed color gems which yield the bonuses of both primary colors associated with that gem.