What can be a good farewell gift to give to my girlfriend?

Last week, her parents got her Engaged to guy a from their Caste. That's how it happens in my country. 4 years of relationship and love we'll have to end now, we have to meet in a few days and break up. It's gonna be very hard since we lived in the same building, and we're friends since childhood all of a sudden she will be married and gone to another City in a different state. Relationships are considered against the religion in most of India, even if you have loads of money you cannot woo your girlfriend's parents if you come from a lower caste.
I'm wondering what can be a good goodbye gift to give her..
Sorry for the bad English.