Where do you get an Eviolite in White?

Question

I heard that if a Pokemon holds a Evolite it makes it better than it's evolved form. Is it true, and where can I get one?

Answer 1

Well, an eviolite makes a Pokemon that is capable of evolution gets their Def and S.def increased by 50%. You can get one in castelia city in the top part of the city(which leads to route 4)It's the Top right building and the scientist gives it to you.

http://www.youtube.com/watch?v=q8o2SScwn9Q