If it's a lot of pigments for a to good to be true price, it's most likely fake. I don't think you can pm until you have more posts, but just post the seller's name.
I don't know about the pigments specifically, but those 12 pan MAC palettes they're selling are definitely fake, and so are the brush sets, so by association, I'd go ahead and assume the pigments are fakes as well.
I took a look at some of the eyeshadow lots they were selling, and the seller actually wrote "This is made in Philippines but the quality is same as the authentic MAC." so they even admit they're fake! I've got to say, that's a first!
Have you ever checked out some of the people that do pigment samples? Those are a better deal, you can get a ton of colors and even 1/4 teaspoon lasts a really long time!