Quote Originally Posted by Unregistered View Post
English wiki and websites used platinium to refer to it when dmm came out and that is all that matters.
The poster you are replying to does not appreciate a general consensus. He's probably going to start a thread polling users on what they call the chests.

- - - Updated - - -

It's less confusing for English sites to refer to it as 'platinum' since it looks like platinum. The actual term for platinum would be 'hakkin'/白金, ie the kanji for 'white' and 'gold'. 虹箱, as used on the wiki, would be 'niji'/'rainbow' and 'hako'/'box or chest'.
If English sites were to refer to these chests as rainbow, we the players would stare at the screen and remark about how they don't freaking look like rainbow.