Whatever the hell it is, fake or not, I purchased one off ebay and got it a week ago, it is seriously the best eye shadow I have ever used, EVER!
It's tricky to put on but it will not budge from your skin until you use make up remover. I put it on to go out and it's still on when i wake up looking perfect. so so vibrant and so metallic. I cant believe how good it is. I freakin love it, I only just realised it may be fake because I was on the mac website looking to buy another several and they just do not exist. Either way I am so stoked on it.