What am I missing on this box puzzle?

[x_equals_speed]

[black] The blue box is empty if it is false

[white] The black box is false
[white2] The above statement is false

[blue] The black box is true and it contains the gems

I got it as

Black - true
White - false (S1 false S2 true)
Blue - true

But that was incorrect.

The only think I can think of is that "The blue box is empty if it is false" should be considered a false statement if the blue box is empty and true?

In conventional logic a statement is not false if it describes an untrue premise. For example "If I had £5 I would be richer" is not automatically falsified if I do not in fact have £5.

Maybe I'm missing something else?

[NoOneOfConsequence]

Your analysis cannot be correct, as none of the boxes contains only false statements.

[x_equals_speed]

Ah, thanks.

I knew there must be at least one true and one false box, but had been treating a box as false if it had one or more false statements.

[jussr]

If one of white's statements is false and the other is true (which is necessary here), then the box does not have only false statements; at least one box with only true statements and at least one with only false is required for the puzzle.

eta: yeah I made the same mistake for a time with the boxes, not realising the full requirements. they get a lot easier once you're actually following the correct rules!