What Is the Chemical Formula of Bornite?

[gracy]

What's the chemical formula of bornite?According to wikipedia
http://en.wikipedia.org/wiki/Bornite
it is Cu5FeS4.According to http://www.spiritofisis.org/knowledge/crystal_files/bornite.htm
it is Cu2FeS4 and as per my textbook it is Cu3FeS2.Now,What's the actual chemical formula of bornite?I am really confused.

 

[Borek]

According to wikipedia

Never hurts to read the entire article:

"Substantial variation in the relative amounts of copper and iron is possible and solid solution extends towards chalcopyrite (CuFeS₂) and digenite (Cu₉S₅). Exsolution of blebs and lamellae of chalcopyrite, digenite, and chalcocite is common."

 

[gracy]

Never hurts to read the entire article:

Yes.You are right.Thanks for your answer @ Borek