do these effects stack

[Noxangelo]

so i was reading the item bible and came across an armor effect that says"This armor makes its wearer appear blurred and hazy, just like the blur spell"

since it says "like the X spell" would this mean while it duplicates the spells effect, the wearer is not under the effect of X spell and therefore the effects, if stackable would stack?

[Aracor]

If it acts as the spell, than the effect is the same and will not stack with the spell.

[Segev]

In addition, as a general rule, similar effects don't stack unless they say they do, and concealment in particular doesn't have a stacking rule, so it doesn't.

[SirNibbles]

In addition, as a general rule, similar effects don't stack unless they say they do, and concealment in particular doesn't have a stacking rule, so it doesn't.

You've got that a bit backwards- things generally stack unless they say they don't. Effects from the same effect don't stack; an item that duplicates a spell effect such as blur is treated as being the same as the blur spell.

Either way, concealment does have a rule on stacking:

"Multiple concealment conditions do not stack." - SRD