In
NetHack, to
identify an
item is to read a
scroll of identify or
cast the
spell of the same name and choose that
item (or get
lucky and have the spell ID everything for you). An indispensable process, as there are numerous items in the
game that are extremely bad to use accidentally -- such as a
scroll of fire,
scroll of amnesia,
potion of paralysis,
wand of cancellation,
amulet of strangulation, and the
list goes
on and on.
Gems and stones you collect are considered worthless until they are identified (and then they're usually worthless anyways). You can only sell a sapphire, for example, to a shopkeeper for full value if you know for a fact that it is a sapphire. Otherwise, he considers it worthless glass and offers accordingly.
You are also given the chance to have your possessions identified when you die. That way, you can moan and groan and smack your head against your desk when you find out that mysterious scroll you had was a blessed scroll of genocide, and that you had a wand of wishing and a ring of slow digestion. The DevTeam always knows how to make me feel better.