Reply #19: The phylactery is what contains the lich's life essence

[NewJeffCT]

If you don't destroy it, you haven't truly destroyed the lich... granted, it's not going to pop up from the ground like a bad horror movie.

The Lich’s Phylactery
An integral part of becoming a lich is creating a magic phylactery in which the character stores its life force. As a rule, the only way to get rid of a lich for sure is to destroy its phylactery. Unless its phylactery is located and destroyed, a lich reappears 1d10 days after its apparent death.

Each lich must make its own phylactery, which requires the Craft Wondrous Item feat. The character must be able to cast spells and have a caster level of 11th or higher. The phylactery costs 120,000 gp and 4,800 XP to create and has a caster level equal to that of its creator at the time of creation.

The most common form of phylactery is a sealed metal box containing strips of parchment on which magical phrases have been transcribed. The box is Tiny and has 40 hit points, hardness 20, and a break DC of 40.

Other forms of phylacteries can exist, such as rings, amulets, or similar items.


http://www.d20srd.org/srd/monsters/lich.htm