Where does it mention to cover the hair specifically in the Quran?

I am a new to the head covering & am aware that it should extend over the chest & bum as mentioned in Surah an Nur however, the word hijaab means modesty/cover where in the Quran does it mention to cover your hair? I know Muslims differ in their opinions & have their own take on this. I would like the FACTS not your own individiual interpretation. I am not referring to hadiths yet, just the Quran in this research :-)