I had my tint done at Cactus Tint in Scottsdale. They showed me the 3M Crystalline and I have it on my windshield. It's not purple at all, in fact it tends toward the warmer, yellower side of the spectrum. According to Rick at Cactus Tint, you can tell it's true 3M Crystalline because there should be a little imprinted 3M in the corner. He showed me where mine is, and said to make sure to look for that because others are claiming to install 3M and charge the same high price, but are actually using different and cheaper films in the back room. I'm not saying this is the case in your situation, but I can say that the 3M Crystalline on my windshield matches up to the yellower color that I saw in the 3M display at the shop. Not purple at all.
Another way to tell that you have true 3M Crystalline or Spectra Photosync is by looking at your tint through polarized sunglasses. You should see a subtle rainbow pattern. If you don't, it's probably not Crystalline or Photosync. I have Spectra Photosync on all of my other windows. That particular brand of tint is very neutral in color.