This magical stone is typically a bit of rough polished agate or similar mineral. 

Its possessor gains a +1 (+5% where applicable) on all dice rolls involving factors such as saving, slipping, dodging, etc.—whenever a die or dice are rolled to find whether the character has an adverse happening befall or not. 

This luck does not affect "to hit" and damage dice or spell failure dice. 

Additionally, the luckstone gives the possessor a +/-1%-10% (at owner's option) on rolls for determination of magic items or division of treasure. The most favorable results will always be gained with a stone of good luck.