Handmade Shawls What Should I Say On A Thank You Card To My Boyfriends Parents?

What should I say on a thank you card to my boyfriends parents? - handmade shawls

They gave me a gift (a beautiful silk dress hand-made) and want to write a thank you card, but I do not know what to say! The Koreans are very sophisticated (read: rich!) And I want to make a big impression on her. Suggestions?