Is there a relationship between the color purple and Star Wars?

I have a Star Wars t-shirt not a huge fan, but it was mainly to make my husband smile, and now it’s one of my favorite shirts and it’s purple with a Star Wars picture on it.
We recently purchased a Star Wars shirt for my son, and it too is purple.
Is that like, the color for Star Wars or something? Am I completely out of the loop on something only fans would know? Or is this just a coincidence?