What is it for?
Jewelcrafting is Burning Crusade' s new tradeskill, and it has two gleaming facets. In the early (pre-60) game, it's used for crafting trinkets, rings and neck slot items. After 60, looted weapons and armor can include "sockets," into which your jewels neatly fit. Jewels then act as personalized upgrades - boosting your statistics.
Where can I find these jewels?
Jewels are created from uncut gems, which have a chance of appearing in ore deposits. Jewelcrafters also have an ability called Prospecting that breaks up five pieces of ore in search of gems - it sometimes comes up blank, but mostly produces a gem or even possibly two. For this reason Mining makes for an excellent companion skill for anyone looking at jewelcrafting. Gems have also been found inside chests. Alternatively such items can be found on the auction house, although obviously for a fee, or from vendors (although these gems tend to be rather basic).
Do I need to be a jewelcrafter to use socket items?
No, anyone can do it provided that they have jewels and a socketed item.
How does it work?
Bring up the socket interface at any time by holding down Shift and right-clicking the socketed item. Basic red, blue and yellow gems only provide a single benefit in a set area, although they can have higher values than other gems.
What's special about the colors?
Multicolored gems combine the benefits of their composite colors - such as the orange gem Glinting Flame Spessarite. This has some of the benefit of red and yellow gems in one convenient package. Such gems count as both colors for the socket bonus, where socketed items often offer a bonus effect if the sockets of the set color are used. For example, a red gem in a red socket, etc. It isn't essential to put a red gem in a red socket, but it's usually worth it.