A cracked pale green prism says
This stone grants a +1 competence bonus on attack rolls or saving throws.
...Whereas the uncracked standard version says
This stone grants the wearer a +1 competence bonus on attack rolls, saves, skill checks, and ability checks.
Does the cracked stone grant:
- +1 competence to both attack rolls and saves?
- +1 competence to either attack rolls or saves (switchable in some fashion by the user)?
- +1 competence to either attack rolls or saves (determined at creation and then unchangeable)?
- ...or something else?
Due to the use of and for the standard (30,000GP) item and the use of or for the cracked (4,000GP) item, I find #1 highly unlikely. I could imagine #2, but my hunch would be that it's #3.