What should I do in the room full of candles?

Hint 1 of 6:

One of these candles is not like the others.

Hint 2 of 6:

The difference is very subtle.

Hint 3 of 6:

In fact, it can only be seen with the mirror sitting in the corner of the
room.

Hint 4 of 6:

Try hanging the mirror from each of the hooks here, until you see the
reflection of a blue flame.

Hint 5 of 6:

The flame whose reflection is blue is the pure fire you need to find -- even
though it looks normal without the mirror.

Hint 6 of 6:

Try locating the blue flame by the surrounding candles, and when you find the
right one, click on it.