According to the Cannabible, there was a strain called Purple Haze that was going around in the 70's. Apparently it wasn't that great and it just went away. There is currently a strain called Purple Haze available in Amsterdam that appears to be a cross between Sensi Star and Purple Power. Ok but nothing special

So, it does exist. But, I'd bet that 99% of what's sold on the street as "Purple Haze" is just some purple weed that the dealer calls Purple Haze in order to jack up the price. Graph had it right: "Purple isn't better. It's just the same as green. There's good, bad, and awful" In other words, never pay premium prices for a name or a color.