Puzzle of the day..The Fake Diamonds - Take Two

King of Einsteinia wanted to marry off his daughter and he devised the 27 diamond challenge to find the most worthy suitor for his daughter. Out of the hundreds of suitors for the princess ten got the correct answer. To find the smartest of the shortlisted suitors, the king devised another challenge.

He got three real diamonds of the same shape, size and weight - one each of blue, pink and white colour. Then he got three fake diamonds of the same colours and mixed them up with the real diamonds. You could not tell the real diamonds from the fake ones by looking at them. All three fake diamonds are of the same weight but a bit lighter than the real diamonds. The new challenge was to separate the real and fake diamonds into two piles using only a simple pan balance. What is the minimum number of weighings required to separate the diamonds? Provide a detailed explanation with your answer.