The darkvision thing is actually only 12000 in 3.5, following the standard spell effect formula of (spell level * caster level * 2000gp), with no adjustment for duration because darkvision is a 1hr/level spell. Both the formula section and the actual magic item description bear this out. Other than that ARandomGod has it right. Subtract 4000 from his prices and they should be accurate. I agree entirely with him that these should be considered multiple similar abilities.
With that in mind, the 3.5 cost for the Moonstone Mask with its abilities as written in the original source should be 15687.5 gp. In my campaign, I'd probably round that to 16000 gp.
With that in mind, the 3.5 cost for the Moonstone Mask with its abilities as written in the original source should be 15687.5 gp. In my campaign, I'd probably round that to 16000 gp.
