Collar of Umbral Metamorphasis

[severed_ronin]

I have a question regarding the Collar of Umbral Metamorphasis from the Tome of Magic. For those who aren't familiar with it, it grants the creature wearing it the Dark template for a specific number of rounds unless you have the advanced version of it which is a continuous effect. The question I have really pertains more towards the addition of the Dark template to a creature. One of the special abilities of the Dark template is granting a character Darkvision 60 ft. Does this Darkvision stack with the racial Darkvision of a Tiefling or Dark Elf or is it simply null and void when applied to those creature types?

 

[StreamOfTheSky]

Unless it mentions stacking or extending a creature's existing darkvision, it probably just uselessly overlaps, because there are several other darkvision granting abilities that DO have a line mentioning a greater range if you already had darkvision. On the plus side, the collar's good for far more than just the darkvision.